simplesnap-1.0.3/0000755000000000000000000000000012277431533010563 5ustar simplesnap-1.0.3/simplesnap0000755000000000000000000002137412277431533012673 0ustar #!/bin/bash # Simple snapshot manager # Copyright (c) 2014 John Goerzen # This program is free software: you can redistribute it and/or modify # it under the terms of the GNU General Public License as published by # the Free Software Foundation, either version 3 of the License, or # (at your option) any later version. # # This program is distributed in the hope that it will be useful, # but WITHOUT ANY WARRANTY; without even the implied warranty of # MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the # GNU General Public License for more details. # # You should have received a copy of the GNU General Public License # along with this program. If not, see . set -e # Log a message logit () { logger -p info -t "`basename $0`[$$]" "$1" } # Log stdin with the given code. Used normally to log stderr. logstdin () { logger -p info -t "`basename $0`[$$/$1]" } # Run command, logging stderr and exit code runcommand () { logit "Running $*" if "$@" 2> >(logstdin "$1") ; then logit "$1 exited successfully" return 0 else RETVAL="$?" logit "$1 exited with error $RETVAL" return "$RETVAL" fi } exiterror () { logit "$1" echo "$1" 1>&2 exit 10 } syntaxerror () { cat < /dev/null || DATE="date" SED="gsed" gsed &> /dev/null || SED="sed" GREP="ggrep" ggrep &> /dev/null || GREP="grep" # Validating [ -n "$SSHCMD" ] || syntaxerror "Invalid SSH command: $SSHCMD" [ -n "$STORE" ] || syntaxerror "Missing --store" [ -n "$SETNAME" ] || syntaxerror "Missing --setname" [ -n "$CHECKMODE" -o -n "$HOST" ] || syntaxerror "Missing --host" echo "_${STORE}" | $GREP -qv " " || syntaxerror "Space in --store: ${STORE}" TEMPLATEPATTERN="^[a-zA-Z0-9]\+\$" echo "a${SETNAME}" | $GREP -q "${TEMPLATEPATTERN}" || syntaxerror "Invalid characters in setname \"${SETNAME}\"; pattern is \"${TEMPLATEPATTERN}\"" echo "_${SETNAME}" | $GREP -qv '^_-' || syntaxerror "Set name cannot begin with a dash: \"${SETNAME}\"" TEMPLATE="__simplesnap_${SETNAME}_" [ -n "$DATASETDEST" -a -z "$BACKUPDATASET" ] && syntaxerror "--datasetdest given without --backupdataset" MOUNTPOINT="`zfs list -H -o mountpoint -t filesystem \"${STORE}\"`" logit "Store ${STORE} is mounted at ${MOUNTPOINT}" cd "${MOUNTPOINT}" # template - $1 # dataset - $2 listsnaps () { runzfs list -t snapshot -r -d 1 -H -o name "$2" | $GREP "@$1" || true } CHECKRETVAL=0 runzfs () { runcommand /sbin/zfs "$@" } checkbackups () { CHECKHOST="$1" DATASETS="`runzfs list -t filesystem,volume -o name -H -r \"${STORE}/${HOST}\"`" CUTOFF="`$DATE -d \"${CHECKMODE}\" +%s`" for CHECKDS in ${DATASETS}; do # Don't check the top-level host dataset itself. if [ "${CHECKDS}" = "${STORE}/${HOST}" ]; then continue fi FOUNDOK=0 # Extract timestamps for TIMESTAMP in `listsnaps "$TEMPLATE" "$CHECKDS" | $SED 's/^.*_\([^_]\+\)__$/\1/'`; do TSSEC=`$DATE -d "${TIMESTAMP}" +%s` if [ "$TSSEC" -gt "$CUTOFF" ]; then FOUNDOK=1 fi done if [ "$FOUNDOK" = "0" ]; then echo "${CHECKDS} last back up is too old; created at `$DATE -d \"@${TSSEC}\"` but cutoff is `$DATE -d \"@${CUTOFF}\"`!" 1>&2 CHECKRETVAL=10 fi done } if [ -n "$CHECKMODE" ]; then # Do a check only. if [ -n "$HOST" ]; then checkbackups "$HOST" else for HOST in *; do checkbackups "$HOST"; done fi logit "check: exiting with value $CHECKRETVAL" exit $CHECKRETVAL fi runwrap () { if [ "$LOCALMODE" = "on" ]; then runcommand "${WRAPCMD}" reinvoked simplesnapwrap "$@" else runcommand ${SSHCMD} ${HOST} ${WRAPCMD} "$@" fi } if [ ! -d "${MOUNTPOINT}/${HOST}" ]; then runzfs create "${STORE}/${HOST}" fi LOCKFILE="${MOUNTPOINT}/${HOST}/.lock" if dotlockfile -r 0 -l -p "${LOCKFILE}"; then LOCKMETHOD="dotlockfile" logit "Lock obtained at ${LOCKFILE} with dotlockfile" trap "ECODE=$?; dotlockfile -u \"${LOCKFILE}\"; exit $ECODE" EXIT INT TERM else RETVAL="$?" if [ "$RETVAL" = "127" ]; then LOCKMETHOD="mkdir" mkdir "${LOCKFILE}" || exiterror "Could not obtain lock at ${LOCKFILE}; if $0 is not already running, rmdir that path." logit "Lock obtained at ${LOCKFILE} with mkdir" trap "ECODE=$?; rmdir \"${LOCKFILE}\"" EXIT INT TERM else exiterror "Could not obtain lock at ${LOCKFILE}; $0 likely already running." fi fi reap () { DATASET="$1" # We always save the most recent. SNAPSTOREMOVE="`listsnaps \"${TEMPLATE}\" \"${DATASET}\" | head -n -1`" if [ -z "${SNAPSTOREMOVE}" ]; then logit "No snapshots to remove." else for REMOVAL in ${SNAPSTOREMOVE}; do logit "Destroying snapshot ${REMOVAL}" echo "_${REMOVAL}" | $GREP -q '@' || exiterror "PANIC: snapshot name doesn not contain @" runzfs destroy "${REMOVAL}" done fi } backupto() { DATASET="$1" DESTDIR="$2" DATASETPATTERN="^[a-zA-Z0-9_/.-]\+\$" if echo "a$DATASET" | $GREP -vq "$DATASETPATTERN"; then logit "Dataset \"$DATASET\" contains invalid characters; pattern is $DATASETPATTERN" return fi if echo "a$DATASET" | $GREP -q "^[/-]"; then exiterror "Dataset \"$DATASET\" begins with a / or a -; something is wrong. Aborting." fi if echo "a$DATASET" | $GREP -q '\.\.'; then exiterror "Dataset \"$DATASET\" contains ..; something is wrong. Aborting." fi if runwrap sendback "${SETNAME}" "${DATASET}" | \ runzfs receive -F "${DESTDIR}"; then logit "Received backup into ${DESTDIR}" runwrap reap "${SETNAME}" "${DATASET}" reap "${DESTDIR}" else logit "zfs receive died with error: $?" exit 100 fi } # If the user requested only one dataset to be backed up: if [ -n "${BACKUPDATASET}" ]; then logit "Option --backupdataset ${BACKUPDATASET} requested; not asking remote for dataset list." # If the user gave a specified location: if [ -n "${DATASETDEST}" ]; then backupto "${BACKUPDATASET}" "${DATASETDEST}" else backupto "${BACKUPDATASET}" "${STORE}/${HOST}/${BACKUPDATASET}" fi else logit "Finding remote datasets to back up" REMOTEDATASETS="`runwrap listfs`" for DATASET in ${REMOTEDATASETS}; do backupto "${DATASET}" "${STORE}/${HOST}/${DATASET}" done fi logit "Exiting successfully." simplesnap-1.0.3/simplesnapwrap0000755000000000000000000001241612277151401013553 0ustar #!/bin/bash # Simple Snapshot Command Wrapper # Copyright (c) 2014 John Goerzen # This program is free software: you can redistribute it and/or modify # it under the terms of the GNU General Public License as published by # the Free Software Foundation, either version 3 of the License, or # (at your option) any later version. # # This program is distributed in the hope that it will be useful, # but WITHOUT ANY WARRANTY; without even the implied warranty of # MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the # GNU General Public License for more details. # # You should have received a copy of the GNU General Public License # along with this program. If not, see . set -e ZFSCMD=/sbin/zfs ZFS=runzfs EXCLUDEPROP="org.complete.simplesnap:exclude" logit () { logger -p info -t "`basename $0`[$$]" "$1" } exiterror () { logit "$1" exit 10 } runzfs () { logit "Running: $ZFSCMD $*" if $ZFSCMD "$@"; then logit "zfs exited successfully." return 0 else RETVAL="$?" logit "zfs exited with error: $RETVAL" return $RETVAL fi } DATE="gdate" gdate &> /dev/null || DATE="date" SED="gsed" gsed &> /dev/null || SED="sed" GREP="ggrep" ggrep &> /dev/null || GREP="grep" # template - $1 # dataset - $2 listsnaps () { $ZFS list -t snapshot -r -d 1 -H -o name "$2" | $GREP "@$1" || true } PATTERN="^[a-zA-Z0-9_/. -]\+\$" if [ "$1" = "reinvoked" ]; then shift logit "Reinvoked with paramters \"$*\"" shift # Drop the call to simplesnapwrap # Validate again. Just to be sure. echo ".$*" | $GREP -q "${PATTERN}" || exiterror "Invalid characters found on re-validate; pattern is ${PATTERN}" echo ".$*" | $GREP -vq '\.\.' || exiterror "Found .. in input; aborting." # We don't want any paramters to contain a space or leading dash. for ARG; do echo ",${ARG}" | $GREP -vq '^,-' || exiterror "Found leading '-' in parameter \"${ARG}\"; aborting." echo ",${ARG}" | $GREP -vq ' ' || exiterror "Found space in parameters; aborting." done MODE="$1" shift || exiterror "Missing mode." case "$MODE" in "listfs") logit "Listing ZFS datasets without ${EXCLUDEPROP}=on" $ZFS list -t filesystem,volume -o "name,${EXCLUDEPROP}" -H | \ $GREP -v $'\ton$' | $SED $'s/\t.*$//' ;; "sendback") # Next lines shared with reap TEMPLATE="__simplesnap_$1_" TEMPLATEPATTERN="^[a-zA-Z0-9]\+\$" echo "a$1" | $GREP -q "${TEMPLATEPATTERN}" || exiterror "Invalid characters in sendback template \"$1\"; pattern is ${TEMPLATEPATTERN}" DATASET="$2" echo "_${DATASET}" | $GREP -vq " " || exiterror "Space found in dataset name" [ -z "${DATASET}" ] && exiterror "No dataset given." [ -z "$1" ] && exiterror "No template given." logit "Listing snapshots on \"${DATASET}\" with template \"${TEMPLATE}\"" OLDESTSNAP="`listsnaps \"${TEMPLATE}\" \"${DATASET}\" | head -n 1`" if [ -z "${OLDESTSNAP}" ]; then logit "Found no existing snapshot." else logit "Will use ${OLDESTSNAP} as basis." fi # Make a new snapshot. NEWSNAP="${TEMPLATE}`$DATE +%FT%T`__" NEWFULLSNAP="${DATASET}@${NEWSNAP}" logit "Making snapshot ${NEWFULLSNAP}" $ZFS snapshot "${NEWFULLSNAP}" if [ -z "${OLDESTSNAP}" ]; then # No existing snapshot. Send the whole thing. logit "Sending non-incremental stream." $ZFS send "${NEWFULLSNAP}" else # Use the oldest existing snapshot. logit "Sending incremental stream back to ${OLDESTSNAP}" $ZFS send -I "${OLDESTSNAP}" "${NEWFULLSNAP}" fi ;; "reap") # Next lines shared with sendback TEMPLATE="__simplesnap_$1_" TEMPLATEPATTERN="^[a-zA-Z0-9_]\+\$" echo "_$TEMPLATE" | $GREP -q "${TEMPLATEPATTERN}" || exiterror "Invalid characters in reap template; pattern is ${TEMPLATEPATTERN}" DATASET="$2" echo "_${DATASET}" | $GREP -vq " " || exiterror "Space found in dataset name" [ -z "${DATASET}" ] && exiterror "No dataset given." [ -z "$1" ] && exiterror "No template given." # We always save the most recent. SNAPSTOREMOVE="`listsnaps \"${TEMPLATE}\" \"${DATASET}\" | head -n -1`" if [ -z "${SNAPSTOREMOVE}" ]; then logit "No snapshots to remove." else for REMOVAL in ${SNAPSTOREMOVE}; do logit "Destroying snapshot ${REMOVAL}" echo "_${REMOVAL}" | $GREP -q '@' || exiterror "PANIC: snapshot name doesn't contain '@'" $ZFS destroy "${REMOVAL}" done fi ;; *) exiterror "Invalid mode \"${MODE}\" specified." ;; esac logit "Exiting successfully." exit 0 fi CMD="${SSH_ORIGINAL_COMMAND}" logit "Invoked with parameters \"$*\" and SSH_ORIGINAL_COMMAND: \"${CMD}\"" if [ -z "${SSH_ORIGINAL_COMMAND}" ]; then echo "simplesnapwrap: This program is to be run from ssh." exiterror "Not run from ssh." fi # Sanitize input. We don't want special characters here. echo ".${CMD}" | $GREP -q "${PATTERN}" || exiterror "Invalid characters in input; pattern is: ${PATTERN}" echo ".${CMD}" | $GREP -vq '\.\.' || exiterror "Found .. in input; aborting." logit "Reinvoking to parse parameters" exec "$0" reinvoked ${CMD} simplesnap-1.0.3/examples/0000755000000000000000000000000012277427766012416 5ustar simplesnap-1.0.3/examples/cron.weekly.zfsnap.serverhost0000644000000000000000000000033712276722267020300 0ustar #!/bin/bash # Create weekly snapshots, lasting 1 month on the serverhost # (expiry time different on the backuphost) # The serverhost daily job will expire them. set -e /usr/sbin/zfSnap -a 1m -p hostname-weekly- -r tank simplesnap-1.0.3/examples/cron.hourly.simplesnap.backuphost0000644000000000000000000000162112276722523021123 0ustar #!/bin/bash # Reach out to each host hourly. This script runs on the backuphost. set -e # We load the SETNAME from a file I created with: # echo setname > /bakfs/local-simplesnap-setname SETNAME="`cat /bakfs/local-simplesnap-setname`" # Or you could simply set it with: # SETNAME="mainset" SSHCMD="ssh -i /root/.ssh/id_rsa_simplesnap" if [ -z "$SETNAME" ]; then echo "Failure: couldn't find a setname" exit 5 fi # Change this to where you store your backups. STORE="bakfs/simplesnap" SIMPLESNAP () { simplesnap --store "$STORE" --setname "$SETNAME" \ --sshcmd "$SSHCMD" "$@" } for HOST in host1 host2 host3 host4; do SIMPLESNAP --host $HOST || echo "Simplesnap failure on host $HOST: $?" done # Only do laptophost at certain times HOUR=`date +%H` if [ "$HOUR" -eq 12 ] || [ "$HOUR" -lt 7 ] || [ "$HOUR" -gt 23 ] ; then SIMPLESNAP --host laptophost || true # laptop, don't squawk fi simplesnap-1.0.3/examples/cron.hourly.zfsnap.serverhost0000644000000000000000000000033612276722361020314 0ustar #!/bin/bash # Create hourly snapshots, lasting 2 days on the serverhost # (expiry time different on the backuphost) # The serverhost daily job will expire them. set -e /usr/sbin/zfSnap -a 2d -p hostname-hourly- -r tank simplesnap-1.0.3/examples/cron.monthly.zfsnap.serverhost0000644000000000000000000000034212276722314020457 0ustar #!/bin/bash # Create monthly snapshots, lasting 3 months on the serverhost # (expiry time different on the backuphost) # The serverhost daily job will expire them. set -e /usr/sbin/zfSnap -a 3m -p hostname-monthly- -r tank simplesnap-1.0.3/examples/cron.daily.simplesnap.backuphost0000644000000000000000000000277412277427766020731 0ustar #!/bin/bash # Daily script to run on the backuphost. Do the check of the backups and # clean up old snapshots. set -e # We load the SETNAME from a file I created with: # echo setname > /bakfs/local-simplesnap-setname SETNAME="`cat /bakfs/local-simplesnap-setname`" # Or you could simply say: # SETNAME="mainset" if [ -z "$SETNAME" ]; then echo "Failure: couldn't find a setname" exit 5 fi # Where your backups are stored STORE="bakfs/simplesnap" SIMPLESNAP () { simplesnap --store "$STORE" --setname "$SETNAME" \ "$@" } if SIMPLESNAP --check '3 days ago'; then for HOSTDS in `zfs list -o name -H -r -d 1 -t filesystem "$STORE"`; do if [ "$HOSTDS" = "$STORE" ]; then continue # Skip the simplesnap dataset itself fi HOSTNAME="`basename ${HOSTDS}`" # Delete hourly snapshots more than 2 days old. zfSnap -v -F 2d -p "${HOSTNAME}-hourly-" # Delete daily snapshots more than 1 month old. zfSnap -v -F 1m -p "${HOSTNAME}-daily-" # Delete weekly snapshots more than 2 months old. zfSnap -v -F 2m -p "${HOSTNAME}-weekly-" # Delete monthly snapshots more than 18 months old. zfSnap -v -F 18m -p "${HOSTNAME}-monthly-" done else echo "Check failed: $?, skipping snapshot cleanup." fi # If using zfSnap, this might be useful to find any extraneous snapshots to remove #if zfs list -H -o name -t snap -r "$STORE" | egrep -v "(-hourly-2|-daily-2|-weekly-2|-monthly-2|@__simplesnap_${SETNAME}_)"; then # echo "Please clean up above snapshots." # exit 5 #fi simplesnap-1.0.3/examples/cron.daily.zfsnap.serverhost0000644000000000000000000000062612276722427020101 0ustar #!/bin/bash # Create daily snapshots lasting 1 week on the serverhost # (different time on the backuphost) set -e /usr/sbin/zfSnap -a 1w -p hostname-daily- -r crypt/jgoerzen tank # Now apply the expiration settings for the other snapshots. /usr/sbin/zfSnap -d -p hostname-hourly- /usr/sbin/zfSnap -d -p hostname-daily- /usr/sbin/zfSnap -d -p hostname-weekly- /usr/sbin/zfSnap -d -p hostname-monthly- simplesnap-1.0.3/debian/0000755000000000000000000000000012277431542012005 5ustar simplesnap-1.0.3/debian/rules0000755000000000000000000000116012276721426013065 0ustar #!/usr/bin/make -f # -*- makefile -*- # Sample debian/rules that uses debhelper. # This file was originally written by Joey Hess and Craig Small. # As a special exception, when this file is copied by dh-make into a # dh-make output file, you may use that output file without restriction. # This special exception was added by Craig Small in version 0.37 of dh-make. # Uncomment this to turn on verbose mode. #export DH_VERBOSE=1 %: dh $@ override_dh_auto_install-indep: install -m 0755 -g root -o root simplesnap debian/simplesnap/usr/sbin/ install -m 0755 -g root -o root simplesnapwrap debian/simplesnap/usr/sbin/ simplesnap-1.0.3/debian/compat0000644000000000000000000000000212276506274013207 0ustar 8 simplesnap-1.0.3/debian/simplesnap.manpages0000644000000000000000000000002112276721127015666 0ustar doc/simplesnap.8 simplesnap-1.0.3/debian/simplesnap.examples0000644000000000000000000000001312276722756015723 0ustar examples/* simplesnap-1.0.3/debian/docs0000644000000000000000000000001312276721042012646 0ustar README.txt simplesnap-1.0.3/debian/dirs0000644000000000000000000000001112276721154012661 0ustar usr/sbin simplesnap-1.0.3/debian/changelog0000644000000000000000000000141112277431533013654 0ustar simplesnap (1.0.3) unstable; urgency=low * Add --backupdataset and --datasetdest options. * Enhance examples and documentation. * Fixed bug in --local -- John Goerzen Fri, 14 Feb 2014 00:22:48 -0600 simplesnap (1.0.2) unstable; urgency=low * Enhanced logging in simplesnapwrap. * Added information about interrogating the backup pool to the manpage. -- John Goerzen Thu, 13 Feb 2014 00:47:10 -0600 simplesnap (1.0.1) unstable; urgency=low * Fixed exit code from simplesnap. -- John Goerzen Wed, 12 Feb 2014 02:45:03 -0600 simplesnap (1.0.0) unstable; urgency=low * Initial Release. Closes: #738740. -- John Goerzen Tue, 11 Feb 2014 00:44:47 -0600 simplesnap-1.0.3/debian/source/0000755000000000000000000000000012276506274013311 5ustar simplesnap-1.0.3/debian/source/format0000644000000000000000000000001512276506274014520 0ustar 3.0 (native) simplesnap-1.0.3/debian/copyright0000644000000000000000000000212112276723070013733 0ustar Format: http://www.debian.org/doc/packaging-manuals/copyright-format/1.0/ Upstream-Name: simplesnap Source: Files: * Copyright: 2014 John Goerzen License: GPL-3.0+ Files: debian/* Copyright: 2014 John Goerzen License: GPL-3.0+ License: GPL-3.0+ This program is free software: you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation, either version 3 of the License, or (at your option) any later version. . This package is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details. . You should have received a copy of the GNU General Public License along with this program. If not, see . . On Debian systems, the complete text of the GNU General Public License version 3 can be found in "/usr/share/common-licenses/GPL-3". simplesnap-1.0.3/debian/control0000644000000000000000000000303412276723271013412 0ustar Source: simplesnap Section: admin Priority: extra Maintainer: John Goerzen Build-Depends: debhelper (>= 8.0.0) Standards-Version: 3.9.3 Homepage: https://github.com/jgoerzen/simplesnap Vcs-Git: https://github.com/jgoerzen/simplesnap.git Vcs-Browser: https://github.com/jgoerzen/simplesnap Package: simplesnap Architecture: all Depends: ${misc:Depends}, zfs-fuse | zfsutils | zfs, liblockfile-bin Suggests: zfsnap Description: Simple and powerful network transmission of ZFS snapshots simplesnap is a simple way to send ZFS snapshots across a net‐ work. Although it can serve many purposes, its primary goal is to manage backups from one ZFS filesystem to a backup filesystem also running ZFS, using incremental backups to minimize network traffic and disk usage. . simplesnap it is designed to perfectly compliment snapshotting tools, permitting rotating backups with arbitrary retention periods. It lets multiple machines back up a single target, lets one machine back up multiple targets, and keeps it all straight. . simplesnap is easy; there is no configuration file needed. One ZFS property is available to exclude datasets/filesystems. ZFS datasets are automatically discovered on machines being backed up. . simplesnap is robust in the face of interrupted transfers, and needs little help to keep running. . nlike many similar tools, simplesnap does not require full root access to the machines being backed up. It runs only a small wrapper as root, and the wrapper has only three commands it implements. simplesnap-1.0.3/COPYING0000644000000000000000000010451312276463635011631 0ustar GNU GENERAL PUBLIC LICENSE Version 3, 29 June 2007 Copyright (C) 2007 Free Software Foundation, Inc. Everyone is permitted to copy and distribute verbatim copies of this license document, but changing it is not allowed. Preamble The GNU General Public License is a free, copyleft license for software and other kinds of works. The licenses for most software and other practical works are designed to take away your freedom to share and change the works. By contrast, the GNU General Public License is intended to guarantee your freedom to share and change all versions of a program--to make sure it remains free software for all its users. We, the Free Software Foundation, use the GNU General Public License for most of our software; it applies also to any other work released this way by its authors. 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But first, please read . simplesnap-1.0.3/INSTALL.txt0000644000000000000000000000157512276502236012440 0ustar PREREQUISITES Requires: * GNU bash * logger (from bsdutils on Linux; ftp://ftp.us.kernel.org/pub/linux/utils/util-linux-ng/ or git://git.debian.org/~lamont/util-linux.git ) Highly recommended: * An automatic snapshotting and rotation system. I use zfSnap from https://github.com/graudeejs/zfSnap * optional but recommended: dotlockfile from liblockfile. This has been tested on Debian Linux with ZFSOnLinux. It will probably work on FreeBSD or Solaris as well, especially if the GNU tools are installed or available under "g" names. The script will try to find them with those names and use them if possible. INSTALLATION Copy simplesnap somewhere on the host that will store backups and mark it executable. Copy simplesnapwrap somewhere on the hosts that will be backed up and mark it executable. If the host storing backups will also be backed up, it needs both. simplesnap-1.0.3/TODO0000644000000000000000000000001612277427766011265 0ustar reapothersets simplesnap-1.0.3/README.txt0000644000000000000000000000072012277427766012275 0ustar simplesnap is a powerful system for transferring ZFS snapshots across a network. It has excellent documentation. See it at: Or, if simplesnap is installed on your system, simply run: man simplesnap See also the examples included in the source distribution. See also my blog post about it: simplesnap-1.0.3/doc/0000755000000000000000000000000012277427766011345 5ustar simplesnap-1.0.3/doc/manpage.links0000644000000000000000000000000012277151521013764 0ustar simplesnap-1.0.3/doc/simplesnap.html0000644000000000000000000010043012277427766014404 0ustar simplesnap

simplesnap

Name

simplesnap -- Simple and powerful way to send ZFS snapshots across a network

Synopsis

simplesnap [--sshcmd COMMAND] [--wrapcmd COMMAND] [--local] [--backupdataset DATASET [--datasetdest DEST]] --store STORE --setname NAME --host HOST

simplesnap --check TIMEFRAME --store STORE --setname NAME [--host HOST]

Description

simplesnap is a simple way to send ZFS snapshots across a network. Although it can serve many purposes, its primary goal is to manage backups from one ZFS filesystem to a backup filesystem also running ZFS, using incremental backups to minimize network traffic and disk usage.

simplesnap is FLEXIBLE; it is designed to perfectly compliment snapshotting tools, permitting rotating backups with arbitrary retention periods. It lets multiple machines back up a single target, lets one machine back up multiple targets, and keeps it all straight.

simplesnap is EASY; there is no configuration file needed. One ZFS property is available to exclude datasets/filesystems. ZFS datasets are automatically discovered on machines being backed up.

simplesnap is SAFE; it is robust in the face of interrupted transfers, and needs little help to keep running.

simplesnap is SECURE; unlike many similar tools, it does not require full root access to the machines being backed up. It runs only a small wrapper as root, and the wrapper has only three commands it implements.

Feature List

Besides the above, simplesnap:

  • Does one thing and does it well. It is designed to be used with a snapshot auto-rotator on both ends (such as zfSnap). simplesnap will transfer snapshots made by other tools, but will not destroy them on either end.

  • Requires ssh public key authorization to the host being backed up, but does not require permission to run arbitrary commands. It has a wrapper to run on the backup host, written in bash, which accepts only three operations and performs them simply. It is suitable for a locked-down authorized_keys file.

  • Creates minimal snapshots for its own internal purposes, generally leaving no more than 1 or 2 per dataset, and reaps them automatically without touching others.

  • Is a small program, easily audited. In fact, most of the code is devoted to sanity-checking, security, and error checking.

  • Automatically discovers what datasets to back up from the remote. Uses a user-defined zfs property to exclude filesystems that should not be backed up.

  • Logs copiously to syslog on all hosts involved in backups.

  • Intelligently supports a single machine being backed up by multiple backup hosts, or onto multiple sets of backup media (when, for instance, backup media is cycled into offsite storage)

Method of Operation

simplesnap's operation is very simple.

The simplesnap program runs on the machine that stores the backups -- we'll call it the backuphost. There is a restricted remote command wrapper called simplesnapwrap that runs on the machine being backed up -- we'll call it the activehost. simplesnapwrap is never invoked directly by the end-user; it is always called remotely by simplesnap.

With simplesnap, the backuphost always connects to the activehost -- never the other way round.

simplesnap runs in the backuphost, and first connects to the simplesnapwrap on the activehost and asks it for a list of the ZFS datasets ("listfs" operation). simplesnapwrap responds with a list of all ZFS datasets that were not flagged for exclusion.

Next, simplesnap connects back to simplesnapwrap once for each dataset to be backed up -- the "sendback" operation. simplesnap passes along to it only two things: the setname and the dataset (filesystem) name.

simplesnapwrap looks to see if there is an existing simplesnap snapshot corresponding to that SETNAME. If not, it creates one and sends it as a full, non-incremental backup. That completes the job for that dataset.

If there is an existing snapshot for that SETNAME, simplesnapwrap creates a new one, constructing the snapshot name containing a timestamp and the SETNAME, then sends an incremental, using the oldest snapshot from that setname as the basis for zfs send -I.

After the backuphost has observed zfs receive exiting without error, it contacts simplesnapwrap once more and requests the "reap" operation. This cleans up the old snapshots for the given SETNAME, leaving only the most recent. This is a separate operation in simplesnapwrap ensuring that even if the transmission is interrupted, still it will be OK in the end because zfs receive -F is used, and the data will come across next time.

The idea is that some system like zfSnap will be used on both ends to make periodic snapshots and clean them up. One can use careful prefix names with zfSnap to use different prefixes on each activehost, and then implement custom cleanup rules with -F on the holderhost.

Quick Start

This section will describe how a first-time simplesnap user can get up and running quickly. It assumes you already have simplesnap installed and working on your system. If not, please follow the instructions in the INSTALL.txt file in the source distribution.

As above, I will refer to the machine storing the backups as the "backuphost" and the machine being backed up as the "activehost".

First, on the backuphost, as root, generate an ssh keypair that will be used exclusively for simplesnap.

ssh-keygen -t rsa -f ~/.ssh/id_rsa_simplesnap

When prompted for a passphrase, leave it empty.

Now, on the activehost, edit or create a file called ~/.ssh/authorized_keys. Initialize it with the content of ~/.ssh/id_rsa_simplesnap.pub from the backuphost. (Or, add to the end, if you already have lines in the file.) Then, at the beginning of that one very long line, add text like this: 

command="/usr/sbin/simplesnapwrap",from="1.2.3.4",
no-port-forwarding,no-X11-forwarding,no-pty

(I broke that line into two for readability, but this must all be on a single line in your file.)

The 1.2.3.4 is the IP address that connections from the backuphost will appear to come from. It may be omitted if the IP is not static, but it affords a little extra security. The line will wind up looking like: 

command="/usr/sbin/simplesnapwrap",from="1.2.3.4",
no-port-forwarding,no-X11-forwarding,no-pty ssh-rsa AAAA....

(Again, this should all be on one huge line.)

If there are any ZFS datasets you do not want to be backed up, set org.complete.simplesnap:exclude property on the activehost to on. For instance:

zfs set org.complete.simplesnap:exclude=on tank/junkdata

Now, back on the backuphost, you should be able to run:

ssh -i ~/.ssh/id_rsa_simplesnap activehost

say yes when asked if you want to add the key to the known_hosts file. At this point, you should see output containing:

"simplesnapwrap: This program is to be run from ssh."

If you see that, then simplesnapwrap was properly invoked remotely.

Now, create a ZFS filesystem to hold your backups. For instance:

zfs create tank/simplesnap

I often recommend compression for simplesnap datasets, so:

zfs set compression=lz4 tank/simplesnap

(If that gives an error, use compression=on instead.)

Now, you can run the backup:

simplesnap --host activehost --setname mainset --store tank/simplesnap --sshcmd "ssh -i /root/.ssh/id_rsa_simplesnap"

You can monitor progress in /var/log/syslog. If all goes well, you will see filesystems start to be populated under tank/simplesnap/host.

Simple!

Now, go test that you have the data you expected to: look at your STORE filesystems and make sure they have everything expected. Test repeatedly over time that you can restore as you expect from your backups.

Advanced: SETNAME usage

Most people will always use the same SETNAME. The SETNAME is used to track and name the snapshots on the remote end. simplesnap tries to always leave one snapshot on the remote, to serve as the base for a future incremental.

In some situations, you may have multiple bases for incrementals. The two primary examples are two different backup servers backing up the same machine, or having two sets of backup media and rotating them to offsite storage. In these situations, you will have to keep different snapshots on the activehost for the different backups, since they will be current to different points in time.

Options

All simplesnap options begin with two dashes (`--'). Most take a parameter, which is to be separated from the option by a space. The equals sign is not a valid separator for simplesnap.

The normal simplesnap mode is backing up. An alternative check mode is available, which requires fewer parameters. This mode is described below.

--backupdataset DATASET

Normally, simplesnap automatically obtains a list of datasets to back up from the remote, and backs up all of them except those that define the org.complete.simplesnap:exclude=on property. With this option, simplesnap does not bother to ask the remote for a list of datasets, and instead backs up only the one precise DATASET given. For now, ignored when --check is given, but that may change in the future. It would be best to not specify this option with --check for now.

--check TIMEFRAME

Do not back up, but check existing backups. If any datasets' newest backup is older than TIMEFRAME, print an error and exit with a nonzero code. Scans all hosts unless a specific host is given with --host. The parameter is in the format given to GNU date(1); for instance, --check "30 days ago". Remember to enclose it in quotes if it contains spaces.

--datasetdest DEST

Valid only with --backupdataset, gives a specific destination for the backup, whith may be outside the STORE. The STORE must still exist, as it is used for storing lockfiles and such.

--host HOST

Gives the name of the host to back up. This is both passed to ssh and used to name the backup sets.

In a few situations, one may not wish to use the same name for both. It is recommend to use the Host and HostName options in ~/.ssh/config to configure aliases in this situation.

--local

Specifies that the host being backed up is local to the machine. Do not use ssh to contact it, and invoke the wrapper directly.

--sshcmd COMMAND

Gives the command to use to connect to the remote host. Defaults to "ssh". It may be used to select an alternative configuration file or keypair. Remember to quote it per your shell if it contains spaces. For example: --sshcmd "ssh -i /root/.id_rsa_simplesnap". This command is ignored when --local or --check is given.

--setname SETNAME

Gives the backup set name. Can just be a made-up word if multiple sets are not needed; for instance, the hostname of the backup server. This is used as part of the snapshot name.

--store STORE

Gives the ZFS dataset name where the data will be stored. Should not begin with a slash. The mountpoint will be obtained from the ZFS subsystem. Always required.

--wrapcmd COMMAND

Gives the path to simplesnapwrap (which must be on the remote machine unless --local is given). Not usually relevant, since the command parameter in ~root/.ssh/authorized_keys gives the path. Default: "simplesnapwrap"

Backup Interrogation

Since simplesnap stores backups in standard ZFS datasets, you can use standard ZFS tools to obtain information about backups. Here are some examples.

Space used per host

Try something like this: 

# zfs list -r -d 1 tank/store
NAME               USED  AVAIL  REFER  MOUNTPOINT
tank/store         540G   867G    34K  /tank/store
tank/store/host1   473G   867G    32K  /tank/store/host1
tank/store/host2  54.9G   867G    32K  /tank/store/host2
tank/store/host3  12.2G   867G    31K  /tank/store/host3

Here, you can see that the total size of the simplesnap data is 540G - the USED value from the top level. In this example, host1 was using the most space -- 473G -- and host3 the least -- 12.2G. There is 867G available on this zpool for backups.

The -r parameter to zfs list requests a recursive report, but the -d 1 parameter sets a maximum depth of 1 -- so you can see just the top-level hosts without all their component datasets.

Space used by a host

Let's say that you had the above example, and want to drill down into more detail. Perhaps, for instance, we continue the above example and drill down into host2: 

# zfs list -r tank/store/host2
NAME                                 USED  AVAIL  REFER  MOUNTPOINT
tank/store/host2                    54.9G   867G    32K  /tank/...
tank/store/host2/tank               49.8G   867G    32K  /tank/...
tank/store/host2/tank/home          7.39G   867G  6.93G  /tank/...
tank/store/host2/tank/vm            42.4G   867G    30K  /tank/...
tank/store/host2/tank/vm/vm1        32.0G   867G  29.7G  -
tank/store/host2/tank/vm/vm2        10.4G   867G  10.4G  -
tank/store/host2/rpool              5.12G   867G    32K  /tank/...
tank/store/host2/rpool/misc          521M   867G   521M  /tank/...
tank/store/host2/rpool/host2-1      4.61G   867G    33K  /tank/...
tank/store/host2/rpool/host2-1/ROOT  317M   867G   312M  /tank/...
tank/store/host2/rpool/host2-1/usr  3.76G   867G  3.76G  /tank/...
tank/store/host2/rpool/host2-1/var   554M   867G   401M  /tank/...

I've trimmed the "mountpoint" column here so it doesn't get too wide for the screen.

You see here the same 54.9G used as in the previous example, but now you can trace it down. There were two zpools on host2: tank and rpool. Most of the backup space -- 49.8G of the 54.9G -- is used by tank, and only 5.12G by rpool. And in tank, 42.4G is used by vm. Tracing it down, of that 42.4G used by vm, 32G is in vm1 and 10.4G in vm2. Notice how the values at each level of the tree include their descendents.

So in this example, vm1 and vm2 are zvols corresponding to virtual machines, and clearly take up a lot of space. Notice how vm1 says it uses 32.0G but in the refer column, it only refers to 29.7G? That means that the latest backup for vm2 used 29.7G, but when you add in the snapshots for that dataset, the total space consumed is 32.0G.

Let's look at an alternative view that will make the size consumed by snapshots more clear: 

# zfs list -o space -r tank/store/host2
NAME                         AVAIL   USED  USEDSNAP  USEDDS  USEDCHILD
.../host2                     867G  54.9G         0     32K      54.9G
.../host2/tank                867G  49.8G         0     32K      49.8G
.../host2/tank/home           867G  7.39G      474M   6.93G          0
.../host2/tank/vm             867G  42.4G       50K     30K      42.4G
.../host2/tank/vm/vm1         867G  32.0G     2.35G   29.7G          0
.../host2/tank/vm/vm1         867G  10.4G       49K   10.4G          0
.../host2/rpool               867G  5.12G         0     32K      5.12G
.../host2/rpool/misc          867G   521M       51K    521M          0
.../host2/rpool/host2-1       867G  4.61G       51K     33K      4.61G
.../host2/rpool/host2-1/ROOT  867G   317M     5.44M    312M          0
.../host2/rpool/host2-1/usr   867G  3.76G      208K   3.76G          0
.../host2/rpool/host2-1/var   867G   554M      153M    401M          0

(Again, I've trimmed some irrelevant columns from this output.)

The AVAIL and USED columns are the same as before, but now you have a breakdown of what makes up the USED column. USEDSNAP is the space used by the snapshots of that particular dataset. USEDDS is the space used by that dataset directly -- the same value as was in REFER before. And USEDCHILD is the space used by descendents of that dataset.

The USEDSNAP column is the easiest way to see the impact your retention policies have on your backup space consumption.

Viewing snapshots of a dataset

Let's take one example from before -- the 153M of snapshots in host2-1/var, and see what we can find. 

# zfs list -t snap -r tank/store/host2/rpool/host2-1/var 
NAME                                              USED  AVAIL  REFER
...
.../var@host2-hourly-2014-02-11_05.17.02--2d       76K      -   402M
.../var@host2-hourly-2014-02-11_06.17.01--2d       77K      -   402M
.../var@host2-hourly-2014-02-11_07.17.01--2d     18.8M      -   402M
.../var@host2-daily-2014-02-11_07.17.25--1w        79K      -   402M
.../var@host2-hourly-2014-02-11_08.17.01--2d      156K      -   402M
.../var@host2-monthly-2014-02-11_09.01.36--1m     114K      -   402M
...

In this output, the REFER column is the amount of data pointed to by that snapshot -- that is, the size of /var at the moment the snapshot is made. And the USED column is the amount of space that would be freed if just that snapshot were deleted.

Note this important point: it is normal for the sum of the values in the USED column to be less than the space consumed by the snapshots of the datasets as reported by USEDSNAP in the previous example. The reason is that the USED column is the data unique to that one snapshot. If, for instance, 100MB of data existed on the system being backed up for three hours yesterday, each snapshot could very well show less than 100KB used, because that 100MB isn't unique to a particular snapshot. Until, that is, two of the three snapshots referncing the 100MB data are destroyed; then the USED value of the last one referencing it will suddenly jump to 100MB higher because now it references unique data.

One other point -- an indication that the last backup was successfully transmitted is the presence of a __simplesnap_...__ snapshot at the end of the list. Do not delete it.

Finding what changed over time

The zfs diff command can let you see what changed over time -- either across a single snapshot, or across many. Let's take a look. 

# zfs diff .../var@host2-hourly-2014-02-11_05.17.02--2d \
  .../var@host2-hourly-2014-02-11_06.17.01--2d \
  | sort -k2 | less
M	/tank/store/host2/rpool/host2-1/var/log/Xorg.0.log
M	/tank/store/host2/rpool/host2-1/var/log/auth.log
M	/tank/store/host2/rpool/host2-1/var/log/daemon.log
...
M	/tank/store/host2/rpool/host2-1/var/spool/anacron/cron.daily
M	/tank/store/host2/rpool/host2-1/var/spool/anacron/cron.monthly
M	/tank/store/host2/rpool/host2-1/var/spool/anacron/cron.weekly
M	/tank/store/host2/rpool/host2-1/var/tmp

Here you can see why there was just a few KB of changes in that snapshot: mostly just a little bit of logging was happening on the system. Now let's inspect the larger snapshot: 

# zfs diff .../var@host2-hourly-2014-02-11_07.17.01--2d \
   .../var@host2-daily-2014-02-11_07.17.25--1w \
   | sort -k2 | less
M	/tank/store/host2/rpool/host2-1/var/backups
+	/tank/store/host2/rpool/host2-1/var/backups/dpkg.status.0
-	/tank/store/host2/rpool/host2-1/var/backups/dpkg.status.0
+	/tank/store/host2/rpool/host2-1/var/backups/dpkg.status.1.gz
R	/tank/store/host2/rpool/host2-1/var/backups/dpkg.status.1.gz -> /tank/store/host2/rpool/host2-1/var/backups/dpkg.status.2.gz
R	/tank/store/host2/rpool/host2-1/var/backups/dpkg.status.2.gz -> /tank/store/host2/rpool/host2-1/var/backups/dpkg.status.3.gz
...
M	/tank/store/host2/rpool/host2-1/var/cache/apt
R	/tank/store/host2/rpool/host2-1/var/cache/apt/pkgcache.bin.KdsMLu -> /tank/store/host2/rpool/host2-1/var/cache/apt/pkgcache.bin

Here you can see some file rotation going on, and a temporary file being renamed to permanent. Normal daily activity on a system, but now you know what was taking up space.

Warnings, Cautions, and Good Practices

Importance of Testing

Any backup scheme should be tested carefully before being relied upon to serve its intended purpose. This item is not simplesnap-specific, but pertains to every backup solution: test that you are backing up the data you expect to before you need it.

Use of zfs receive -F

In order to account for various situations that could lead to divergence of filesystems, including the simple act of mounting them, simplesnap always uses zfs receive -F. Any local changes you make to the simplesnap store datasets will be lost at any time. If you need to make local changes there, it is best to copy them elsewhere.

Extraneous Snapshot Buildup

Since simplesnap sends all snapshots, it is possible that locally-created snapshots made outside of your rotation scheme will also be sent to your backuphost. These may not be automatically reaped there, and may stick around. An example at the end of the cron.daily.simplesnap.backuphost file included with simplesnap is one way to check for these. They could automatically be reaped with zfs destroy as well, but this must be carefully tuned to local requirements, so an example of doign that is intentionally not supplied with the distribution.

Internal simplesnap snapshots

simplesnap creates snapshots beginning with __simplesnap_ followed by your SETNAME. Do not create, remove, or alter these snapshots in any way, either on the activehost or the backuphost. Doing so may lead to unpredictable side-effects.

Bugs

Ordinarily, an interrupted transfer is no problem for simplesnap. However, the very first transfer of a dataset poses a bit of a problem, since the simplesnap wrapper can't detect failure in this one special case. If your first transfer gets interrupted, simply zfs destroy the __simplesnap_...__ snapshot on the activehost and rerun. NEVER DESTROY __simplesnap SNAPSHOTS IN ANY OTHER SITUATION!

See Also

zfSnap (1), zfs (8).

The simplesnap homepage: https://github.com/jgoerzen/simplesnap

The examples included with the simplesnap distribution, or on its homepage.

The zfSnap package compliments simplesnap perfectly. Find it at https://github.com/graudeejs/zfSnap.

AUTHOR

This software and manual page was written by John Goerzen . Permission is granted to copy, distribute and/or modify this document under the terms of the GNU General Public License, Version 3 any later version published by the Free Software Foundation. The complete text of the GNU General Public License is included in the file COPYING in the source distribution.

simplesnap-1.0.3/doc/simplesnap.sgml0000644000000000000000000010327412277427766014413 0ustar manpage.1'. You may view the manual page with: `docbook-to-man manpage.sgml | nroff -man | less'. A typical entry in a Makefile or Makefile.am is: manpage.1: manpage.sgml docbook-to-man $< > $@ The docbook-to-man binary is found in the docbook-to-man package. Please remember that if you create the nroff version in one of the debian/rules file targets (such as build), you will need to include docbook-to-man in your Build-Depends control field. --> JOHN"> GOERZEN"> 8"> jgoerzen@complete.org"> simplesnap"> simplesnap"> Debian"> GNU"> GPL"> ]>
&dhemail;
&dhfirstname; &dhsurname; 2014 &dhusername; &dhucpackage; &dhsection; &dhpackage; Simple and powerful way to send ZFS snapshots across a network &dhpackage; COMMAND COMMAND DATASET DEST STORE NAME HOST &dhpackage; TIMEFRAME STORE NAME HOST Description &simplesnap; is a simple way to send ZFS snapshots across a network. Although it can serve many purposes, its primary goal is to manage backups from one ZFS filesystem to a backup filesystem also running ZFS, using incremental backups to minimize network traffic and disk usage. &simplesnap; is FLEXIBLE; it is designed to perfectly compliment snapshotting tools, permitting rotating backups with arbitrary retention periods. It lets multiple machines back up a single target, lets one machine back up multiple targets, and keeps it all straight. &simplesnap; is EASY; there is no configuration file needed. One ZFS property is available to exclude datasets/filesystems. ZFS datasets are automatically discovered on machines being backed up. &simplesnap; is SAFE; it is robust in the face of interrupted transfers, and needs little help to keep running. &simplesnap; is SECURE; unlike many similar tools, it does not require full root access to the machines being backed up. It runs only a small wrapper as root, and the wrapper has only three commands it implements. Feature List Besides the above, &simplesnap;: Does one thing and does it well. It is designed to be used with a snapshot auto-rotator on both ends (such as zfSnap). simplesnap will transfer snapshots made by other tools, but will not destroy them on either end. Requires ssh public key authorization to the host being backed up, but does not require permission to run arbitrary commands. It has a wrapper to run on the backup host, written in bash, which accepts only three operations and performs them simply. It is suitable for a locked-down authorized_keys file. Creates minimal snapshots for its own internal purposes, generally leaving no more than 1 or 2 per dataset, and reaps them automatically without touching others. Is a small program, easily audited. In fact, most of the code is devoted to sanity-checking, security, and error checking. Automatically discovers what datasets to back up from the remote. Uses a user-defined zfs property to exclude filesystems that should not be backed up. Logs copiously to syslog on all hosts involved in backups. Intelligently supports a single machine being backed up by multiple backup hosts, or onto multiple sets of backup media (when, for instance, backup media is cycled into offsite storage) Method of Operation &simplesnap;'s operation is very simple. The simplesnap program runs on the machine that stores the backups -- we'll call it the backuphost. There is a restricted remote command wrapper called simplesnapwrap that runs on the machine being backed up -- we'll call it the activehost. simplesnapwrap is never invoked directly by the end-user; it is always called remotely by simplesnap. With &simplesnap;, the backuphost always connects to the activehost -- never the other way round. simplesnap runs in the backuphost, and first connects to the simplesnapwrap on the activehost and asks it for a list of the ZFS datasets ("listfs" operation). simplesnapwrap responds with a list of all ZFS datasets that were not flagged for exclusion. Next, simplesnap connects back to simplesnapwrap once for each dataset to be backed up -- the "sendback" operation. simplesnap passes along to it only two things: the setname and the dataset (filesystem) name. simplesnapwrap looks to see if there is an existing simplesnap snapshot corresponding to that SETNAME. If not, it creates one and sends it as a full, non-incremental backup. That completes the job for that dataset. If there is an existing snapshot for that SETNAME, simplesnapwrap creates a new one, constructing the snapshot name containing a timestamp and the SETNAME, then sends an incremental, using the oldest snapshot from that setname as the basis for zfs send -I. After the backuphost has observed zfs receive exiting without error, it contacts simplesnapwrap once more and requests the "reap" operation. This cleans up the old snapshots for the given SETNAME, leaving only the most recent. This is a separate operation in simplesnapwrap ensuring that even if the transmission is interrupted, still it will be OK in the end because zfs receive -F is used, and the data will come across next time. The idea is that some system like zfSnap will be used on both ends to make periodic snapshots and clean them up. One can use careful prefix names with zfSnap to use different prefixes on each activehost, and then implement custom cleanup rules with -F on the holderhost. Quick Start This section will describe how a first-time &simplesnap; user can get up and running quickly. It assumes you already have &simplesnap; installed and working on your system. If not, please follow the instructions in the INSTALL.txt file in the source distribution. As above, I will refer to the machine storing the backups as the "backuphost" and the machine being backed up as the "activehost". First, on the backuphost, as root, generate an ssh keypair that will be used exclusively for &simplesnap;. ssh-keygen -t rsa -f ~/.ssh/id_rsa_simplesnap When prompted for a passphrase, leave it empty. Now, on the activehost, edit or create a file called ~/.ssh/authorized_keys. Initialize it with the content of ~/.ssh/id_rsa_simplesnap.pub from the backuphost. (Or, add to the end, if you already have lines in the file.) Then, at the beginning of that one very long line, add text like this: (I broke that line into two for readability, but this must all be on a single line in your file.) The 1.2.3.4 is the IP address that connections from the backuphost will appear to come from. It may be omitted if the IP is not static, but it affords a little extra security. The line will wind up looking like: (Again, this should all be on one huge line.) If there are any ZFS datasets you do not want to be backed up, set org.complete.simplesnap:exclude property on the activehost to on. For instance: zfs set org.complete.simplesnap:exclude=on tank/junkdata Now, back on the backuphost, you should be able to run: ssh -i ~/.ssh/id_rsa_simplesnap activehost say yes when asked if you want to add the key to the known_hosts file. At this point, you should see output containing: "simplesnapwrap: This program is to be run from ssh." If you see that, then simplesnapwrap was properly invoked remotely. Now, create a ZFS filesystem to hold your backups. For instance: zfs create tank/simplesnap I often recommend compression for &simplesnap; datasets, so: zfs set compression=lz4 tank/simplesnap (If that gives an error, use compression=on instead.) Now, you can run the backup: simplesnap --host activehost --setname mainset --store tank/simplesnap --sshcmd "ssh -i /root/.ssh/id_rsa_simplesnap" You can monitor progress in /var/log/syslog. If all goes well, you will see filesystems start to be populated under tank/simplesnap/host. Simple! Now, go test that you have the data you expected to: look at your STORE filesystems and make sure they have everything expected. Test repeatedly over time that you can restore as you expect from your backups. Advanced: SETNAME usage Most people will always use the same SETNAME. The SETNAME is used to track and name the snapshots on the remote end. simplesnap tries to always leave one snapshot on the remote, to serve as the base for a future incremental. In some situations, you may have multiple bases for incrementals. The two primary examples are two different backup servers backing up the same machine, or having two sets of backup media and rotating them to offsite storage. In these situations, you will have to keep different snapshots on the activehost for the different backups, since they will be current to different points in time. Options All &simplesnap; options begin with two dashes (`--'). Most take a parameter, which is to be separated from the option by a space. The equals sign is not a valid separator for &simplesnap;. The normal &simplesnap; mode is backing up. An alternative check mode is available, which requires fewer parameters. This mode is described below. Normally, &simplesnap; automatically obtains a list of datasets to back up from the remote, and backs up all of them except those that define the org.complete.simplesnap:exclude=on property. With this option, &simplesnap; does not bother to ask the remote for a list of datasets, and instead backs up only the one precise DATASET given. For now, ignored when is given, but that may change in the future. It would be best to not specify this option with --check for now. Do not back up, but check existing backups. If any datasets' newest backup is older than TIMEFRAME, print an error and exit with a nonzero code. Scans all hosts unless a specific host is given with . The parameter is in the format given to GNU date(1); for instance, --check "30 days ago". Remember to enclose it in quotes if it contains spaces. Valid only with , gives a specific destination for the backup, whith may be outside the STORE. The STORE must still exist, as it is used for storing lockfiles and such. HOST Gives the name of the host to back up. This is both passed to ssh and used to name the backup sets. In a few situations, one may not wish to use the same name for both. It is recommend to use the Host and HostName options in ~/.ssh/config to configure aliases in this situation. Specifies that the host being backed up is local to the machine. Do not use ssh to contact it, and invoke the wrapper directly. Gives the command to use to connect to the remote host. Defaults to "ssh". It may be used to select an alternative configuration file or keypair. Remember to quote it per your shell if it contains spaces. For example: --sshcmd "ssh -i /root/.id_rsa_simplesnap". This command is ignored when or is given. Gives the backup set name. Can just be a made-up word if multiple sets are not needed; for instance, the hostname of the backup server. This is used as part of the snapshot name. Gives the ZFS dataset name where the data will be stored. Should not begin with a slash. The mountpoint will be obtained from the ZFS subsystem. Always required. Gives the path to simplesnapwrap (which must be on the remote machine unless is given). Not usually relevant, since the command parameter in ~root/.ssh/authorized_keys gives the path. Default: "simplesnapwrap" Backup Interrogation Since &simplesnap; stores backups in standard ZFS datasets, you can use standard ZFS tools to obtain information about backups. Here are some examples. Space used per host Try something like this: Here, you can see that the total size of the &simplesnap; data is 540G - the USED value from the top level. In this example, host1 was using the most space -- 473G -- and host3 the least -- 12.2G. There is 867G available on this zpool for backups. The -r parameter to zfs list requests a recursive report, but the -d 1 parameter sets a maximum depth of 1 -- so you can see just the top-level hosts without all their component datasets. Space used by a host Let's say that you had the above example, and want to drill down into more detail. Perhaps, for instance, we continue the above example and drill down into host2: I've trimmed the "mountpoint" column here so it doesn't get too wide for the screen. You see here the same 54.9G used as in the previous example, but now you can trace it down. There were two zpools on host2: tank and rpool. Most of the backup space -- 49.8G of the 54.9G -- is used by tank, and only 5.12G by rpool. And in tank, 42.4G is used by vm. Tracing it down, of that 42.4G used by vm, 32G is in vm1 and 10.4G in vm2. Notice how the values at each level of the tree include their descendents. So in this example, vm1 and vm2 are zvols corresponding to virtual machines, and clearly take up a lot of space. Notice how vm1 says it uses 32.0G but in the refer column, it only refers to 29.7G? That means that the latest backup for vm2 used 29.7G, but when you add in the snapshots for that dataset, the total space consumed is 32.0G. Let's look at an alternative view that will make the size consumed by snapshots more clear: (Again, I've trimmed some irrelevant columns from this output.) The AVAIL and USED columns are the same as before, but now you have a breakdown of what makes up the USED column. USEDSNAP is the space used by the snapshots of that particular dataset. USEDDS is the space used by that dataset directly -- the same value as was in REFER before. And USEDCHILD is the space used by descendents of that dataset. The USEDSNAP column is the easiest way to see the impact your retention policies have on your backup space consumption. Viewing snapshots of a dataset Let's take one example from before -- the 153M of snapshots in host2-1/var, and see what we can find. In this output, the REFER column is the amount of data pointed to by that snapshot -- that is, the size of /var at the moment the snapshot is made. And the USED column is the amount of space that would be freed if just that snapshot were deleted. Note this important point: it is normal for the sum of the values in the USED column to be less than the space consumed by the snapshots of the datasets as reported by USEDSNAP in the previous example. The reason is that the USED column is the data unique to that one snapshot. If, for instance, 100MB of data existed on the system being backed up for three hours yesterday, each snapshot could very well show less than 100KB used, because that 100MB isn't unique to a particular snapshot. Until, that is, two of the three snapshots referncing the 100MB data are destroyed; then the USED value of the last one referencing it will suddenly jump to 100MB higher because now it references unique data. One other point -- an indication that the last backup was successfully transmitted is the presence of a __simplesnap_...__ snapshot at the end of the list. Do not delete it. Finding what changed over time The zfs diff command can let you see what changed over time -- either across a single snapshot, or across many. Let's take a look. Here you can see why there was just a few KB of changes in that snapshot: mostly just a little bit of logging was happening on the system. Now let's inspect the larger snapshot: /tank/store/host2/rpool/host2-1/var/backups/dpkg.status.2.gz R /tank/store/host2/rpool/host2-1/var/backups/dpkg.status.2.gz -> /tank/store/host2/rpool/host2-1/var/backups/dpkg.status.3.gz ... M /tank/store/host2/rpool/host2-1/var/cache/apt R /tank/store/host2/rpool/host2-1/var/cache/apt/pkgcache.bin.KdsMLu -> /tank/store/host2/rpool/host2-1/var/cache/apt/pkgcache.bin ]]> Here you can see some file rotation going on, and a temporary file being renamed to permanent. Normal daily activity on a system, but now you know what was taking up space. Warnings, Cautions, and Good Practices Importance of Testing Any backup scheme should be tested carefully before being relied upon to serve its intended purpose. This item is not &simplesnap;-specific, but pertains to every backup solution: test that you are backing up the data you expect to before you need it. Use of zfs receive -F In order to account for various situations that could lead to divergence of filesystems, including the simple act of mounting them, &simplesnap; always uses zfs receive -F. Any local changes you make to the &simplesnap; store datasets will be lost at any time. If you need to make local changes there, it is best to copy them elsewhere. Extraneous Snapshot Buildup Since &simplesnap; sends all snapshots, it is possible that locally-created snapshots made outside of your rotation scheme will also be sent to your backuphost. These may not be automatically reaped there, and may stick around. An example at the end of the cron.daily.simplesnap.backuphost file included with &simplesnap; is one way to check for these. They could automatically be reaped with zfs destroy as well, but this must be carefully tuned to local requirements, so an example of doign that is intentionally not supplied with the distribution. Internal simplesnap snapshots &simplesnap; creates snapshots beginning with __simplesnap_ followed by your SETNAME. Do not create, remove, or alter these snapshots in any way, either on the activehost or the backuphost. Doing so may lead to unpredictable side-effects. Bugs Ordinarily, an interrupted transfer is no problem for &simplesnap;. However, the very first transfer of a dataset poses a bit of a problem, since the &simplesnap; wrapper can't detect failure in this one special case. If your first transfer gets interrupted, simply zfs destroy the __simplesnap_...__ snapshot on the activehost and rerun. NEVER DESTROY __simplesnap SNAPSHOTS IN ANY OTHER SITUATION! See Also zfSnap (1), zfs (8). The &simplesnap; homepage: The examples included with the &simplesnap; distribution, or on its homepage. The zfSnap package compliments &simplesnap; perfectly. Find it at . AUTHOR This software and manual page was written by &dhusername; &dhemail;. Permission is granted to copy, distribute and/or modify this document under the terms of the &gnu; General Public License, Version 3 any later version published by the Free Software Foundation. The complete text of the GNU General Public License is included in the file COPYING in the source distribution. simplesnap-1.0.3/doc/simplesnap.80000644000000000000000000005603612277427766013623 0ustar .\" This manpage has been automatically generated by docbook2man .\" from a DocBook document. This tool can be found at: .\" .\" Please send any bug reports, improvements, comments, patches, .\" etc. to Steve Cheng . .TH "SIMPLESNAP" "8" "14 February 2014" "" "" .SH NAME simplesnap \- Simple and powerful way to send ZFS snapshots across a network .SH SYNOPSIS \fBsimplesnap\fR [ \fB--sshcmd \fICOMMAND\fB\fR ] [ \fB--wrapcmd \fICOMMAND\fB\fR ] [ \fB--local\fR ] [ \fB--backupdataset \fIDATASET\fB [ --datasetdest \fIDEST\fB ]\fR ] \fB--store \fISTORE\fB\fR \fB--setname \fINAME\fB\fR \fB--host \fIHOST\fB\fR \fBsimplesnap\fR \fB--check \fITIMEFRAME\fB\fR \fB--store \fISTORE\fB\fR \fB--setname \fINAME\fB\fR [ \fB--host \fIHOST\fB\fR ] .SH "DESCRIPTION" .PP \fBsimplesnap\fR is a simple way to send ZFS snapshots across a network. Although it can serve many purposes, its primary goal is to manage backups from one ZFS filesystem to a backup filesystem also running ZFS, using incremental backups to minimize network traffic and disk usage. .PP \fBsimplesnap\fR is \fBFLEXIBLE\fR; it is designed to perfectly compliment snapshotting tools, permitting rotating backups with arbitrary retention periods. It lets multiple machines back up a single target, lets one machine back up multiple targets, and keeps it all straight. .PP \fBsimplesnap\fR is \fBEASY\fR; there is no configuration file needed. One ZFS property is available to exclude datasets/filesystems. ZFS datasets are automatically discovered on machines being backed up. .PP \fBsimplesnap\fR is \fBSAFE\fR; it is robust in the face of interrupted transfers, and needs little help to keep running. .PP \fBsimplesnap\fR is \fBSECURE\fR; unlike many similar tools, it does not require full root access to the machines being backed up. It runs only a small wrapper as root, and the wrapper has only three commands it implements. .SS "FEATURE LIST" .PP Besides the above, \fBsimplesnap\fR: .TP 0.2i \(bu Does one thing and does it well. It is designed to be used with a snapshot auto-rotator on both ends (such as zfSnap). simplesnap will transfer snapshots made by other tools, but will not destroy them on either end. .TP 0.2i \(bu Requires ssh public key authorization to the host being backed up, but does not require permission to run arbitrary commands. It has a wrapper to run on the backup host, written in bash, which accepts only three operations and performs them simply. It is suitable for a locked-down authorized_keys file. .TP 0.2i \(bu Creates minimal snapshots for its own internal purposes, generally leaving no more than 1 or 2 per dataset, and reaps them automatically without touching others. .TP 0.2i \(bu Is a small program, easily audited. In fact, most of the code is devoted to sanity-checking, security, and error checking. .TP 0.2i \(bu Automatically discovers what datasets to back up from the remote. Uses a user-defined zfs property to exclude filesystems that should not be backed up. .TP 0.2i \(bu Logs copiously to syslog on all hosts involved in backups. .TP 0.2i \(bu Intelligently supports a single machine being backed up by multiple backup hosts, or onto multiple sets of backup media (when, for instance, backup media is cycled into offsite storage) .SS "METHOD OF OPERATION" .PP \fBsimplesnap\fR\&'s operation is very simple. .PP The \fBsimplesnap\fR program runs on the machine that stores the backups -- we'll call it the backuphost. There is a restricted remote command wrapper called \fBsimplesnapwrap\fR that runs on the machine being backed up -- we'll call it the activehost. \fBsimplesnapwrap\fR is never invoked directly by the end-user; it is always called remotely by \fBsimplesnap\fR\&. .PP With \fBsimplesnap\fR, the backuphost always connects to the activehost -- never the other way round. .PP \fBsimplesnap\fR runs in the backuphost, and first connects to the \fBsimplesnapwrap\fR on the activehost and asks it for a list of the ZFS datasets ("listfs" operation). \fBsimplesnapwrap\fR responds with a list of all ZFS datasets that were not flagged for exclusion. .PP Next, \fBsimplesnap\fR connects back to \fBsimplesnapwrap\fR once for each dataset to be backed up -- the "sendback" operation. \fBsimplesnap\fR passes along to it only two things: the setname and the dataset (filesystem) name. .PP \fBsimplesnapwrap\fR looks to see if there is an existing simplesnap snapshot corresponding to that \fISETNAME\fR\&. If not, it creates one and sends it as a full, non-incremental backup. That completes the job for that dataset. .PP If there is an existing snapshot for that \fISETNAME\fR, simplesnapwrap creates a new one, constructing the snapshot name containing a timestamp and the \fISETNAME\fR, then sends an incremental, using the oldest snapshot from that setname as the basis for zfs send -I. .PP After the backuphost has observed \fBzfs receive\fR exiting without error, it contacts \fBsimplesnapwrap\fR once more and requests the "reap" operation. This cleans up the old snapshots for the given \fISETNAME\fR, leaving only the most recent. This is a separate operation in \fBsimplesnapwrap\fR ensuring that even if the transmission is interrupted, still it will be OK in the end because \fBzfs receive -F\fR is used, and the data will come across next time. .PP The idea is that some system like \fBzfSnap\fR will be used on both ends to make periodic snapshots and clean them up. One can use careful prefix names with zfSnap to use different prefixes on each activehost, and then implement custom cleanup rules with -F on the holderhost. .SH "QUICK START" .PP This section will describe how a first-time \fBsimplesnap\fR user can get up and running quickly. It assumes you already have \fBsimplesnap\fR installed and working on your system. If not, please follow the instructions in the \fIINSTALL.txt\fR file in the source distribution. .PP As above, I will refer to the machine storing the backups as the "backuphost" and the machine being backed up as the "activehost". .PP First, on the backuphost, as root, generate an ssh keypair that will be used exclusively for \fBsimplesnap\fR\&. .PP \fBssh-keygen -t rsa -f ~/.ssh/id_rsa_simplesnap\fR .PP When prompted for a passphrase, leave it empty. .PP Now, on the activehost, edit or create a file called \fI~/.ssh/authorized_keys\fR\&. Initialize it with the content of \fI~/.ssh/id_rsa_simplesnap.pub\fR from the backuphost. (Or, add to the end, if you already have lines in the file.) Then, at the beginning of that one very long line, add text like this: .nf command="/usr/sbin/simplesnapwrap",from="1.2.3.4", no-port-forwarding,no-X11-forwarding,no-pty .fi .PP (I broke that line into two for readability, but this must all be on a single line in your file.) .PP The \fI1.2.3.4\fR is the IP address that connections from the backuphost will appear to come from. It may be omitted if the IP is not static, but it affords a little extra security. The line will wind up looking like: .nf command="/usr/sbin/simplesnapwrap",from="1.2.3.4", no-port-forwarding,no-X11-forwarding,no-pty ssh-rsa AAAA.... .fi .PP (Again, this should all be on one huge line.) .PP If there are any ZFS datasets you do not want to be backed up, set \fIorg.complete.simplesnap:exclude\fR property on the activehost to \fIon\fR\&. For instance: .PP \fBzfs set org.complete.simplesnap:exclude=on tank/junkdata\fR .PP Now, back on the backuphost, you should be able to run: .PP \fBssh -i ~/.ssh/id_rsa_simplesnap activehost\fR .PP say yes when asked if you want to add the key to the known_hosts file. At this point, you should see output containing: .PP "simplesnapwrap: This program is to be run from ssh." .PP If you see that, then simplesnapwrap was properly invoked remotely. .PP Now, create a ZFS filesystem to hold your backups. For instance: .PP \fBzfs create tank/simplesnap\fR .PP I often recommend compression for \fBsimplesnap\fR datasets, so: .PP \fBzfs set compression=lz4 tank/simplesnap\fR .PP (If that gives an error, use compression=on instead.) .PP Now, you can run the backup: .PP \fBsimplesnap --host activehost --setname mainset --store tank/simplesnap --sshcmd "ssh -i /root/.ssh/id_rsa_simplesnap" \fR .PP You can monitor progress in \fI/var/log/syslog\fR\&. If all goes well, you will see filesystems start to be populated under \fItank/simplesnap/host\fR\&. .PP Simple! .PP Now, go test that you have the data you expected to: look at your \fISTORE\fR filesystems and make sure they have everything expected. Test repeatedly over time that you can restore as you expect from your backups. .SH "ADVANCED: SETNAME USAGE" .PP Most people will always use the same \fISETNAME\fR\&. The \fISETNAME\fR is used to track and name the snapshots on the remote end. simplesnap tries to always leave one snapshot on the remote, to serve as the base for a future incremental. .PP In some situations, you may have multiple bases for incrementals. The two primary examples are two different backup servers backing up the same machine, or having two sets of backup media and rotating them to offsite storage. In these situations, you will have to keep different snapshots on the activehost for the different backups, since they will be current to different points in time. .SH "OPTIONS" .PP All \fBsimplesnap\fR options begin with two dashes (`--'). Most take a parameter, which is to be separated from the option by a space. The equals sign is not a valid separator for \fBsimplesnap\fR\&. .PP The normal \fBsimplesnap\fR mode is backing up. An alternative check mode is available, which requires fewer parameters. This mode is described below. .TP \fB--backupdataset \fIDATASET\fB \fR Normally, \fBsimplesnap\fR automatically obtains a list of datasets to back up from the remote, and backs up all of them except those that define the \fIorg.complete.simplesnap:exclude=on\fR property. With this option, \fBsimplesnap\fR does not bother to ask the remote for a list of datasets, and instead backs up only the one precise \fIDATASET\fR given. For now, ignored when \fB--check\fR is given, but that may change in the future. It would be best to not specify this option with --check for now. .TP \fB--check \fITIMEFRAME\fB \fR Do not back up, but check existing backups. If any datasets' newest backup is older than \fITIMEFRAME\fR, print an error and exit with a nonzero code. Scans all hosts unless a specific host is given with \fB--host\fR\&. The parameter is in the format given to GNU \fBdate\fR(1); for instance, --check "30 days ago". Remember to enclose it in quotes if it contains spaces. .TP \fB--datasetdest \fIDEST\fB \fR Valid only with \fB--backupdataset\fR, gives a specific destination for the backup, whith may be outside the \fISTORE\fR\&. The \fISTORE\fR must still exist, as it is used for storing lockfiles and such. .TP \fB--host \fIHOST\fB\fR Gives the name of the host to back up. This is both passed to ssh and used to name the backup sets. In a few situations, one may not wish to use the same name for both. It is recommend to use the Host and HostName options in \fI~/.ssh/config\fR to configure aliases in this situation. .TP \fB--local \fR Specifies that the host being backed up is local to the machine. Do not use ssh to contact it, and invoke the wrapper directly. .TP \fB--sshcmd \fICOMMAND\fB \fR Gives the command to use to connect to the remote host. Defaults to "ssh". It may be used to select an alternative configuration file or keypair. Remember to quote it per your shell if it contains spaces. For example: --sshcmd "ssh -i /root/.id_rsa_simplesnap". This command is ignored when \fB--local\fR or \fB--check\fR is given. .TP \fB--setname \fISETNAME\fB\fR Gives the backup set name. Can just be a made-up word if multiple sets are not needed; for instance, the hostname of the backup server. This is used as part of the snapshot name. .TP \fB--store \fISTORE\fB \fR Gives the ZFS dataset name where the data will be stored. Should not begin with a slash. The mountpoint will be obtained from the ZFS subsystem. Always required. .TP \fB--wrapcmd \fICOMMAND\fB \fR Gives the path to simplesnapwrap (which must be on the remote machine unless \fB--local\fR is given). Not usually relevant, since the \fIcommand\fR parameter in \fI~root/.ssh/authorized_keys\fR gives the path. Default: "simplesnapwrap" .SH "BACKUP INTERROGATION" .PP Since \fBsimplesnap\fR stores backups in standard ZFS datasets, you can use standard ZFS tools to obtain information about backups. Here are some examples. .SS "SPACE USED PER HOST" .PP Try something like this: .nf # zfs list -r -d 1 tank/store NAME USED AVAIL REFER MOUNTPOINT tank/store 540G 867G 34K /tank/store tank/store/host1 473G 867G 32K /tank/store/host1 tank/store/host2 54.9G 867G 32K /tank/store/host2 tank/store/host3 12.2G 867G 31K /tank/store/host3 .fi .PP Here, you can see that the total size of the \fBsimplesnap\fR data is 540G - the USED value from the top level. In this example, host1 was using the most space -- 473G -- and host3 the least -- 12.2G. There is 867G available on this zpool for backups. .PP The \fI-r\fR parameter to \fBzfs list\fR requests a recursive report, but the \fI-d 1\fR parameter sets a maximum depth of 1 -- so you can see just the top-level hosts without all their component datasets. .SS "SPACE USED BY A HOST" .PP Let's say that you had the above example, and want to drill down into more detail. Perhaps, for instance, we continue the above example and drill down into host2: .nf # zfs list -r tank/store/host2 NAME USED AVAIL REFER MOUNTPOINT tank/store/host2 54.9G 867G 32K /tank/... tank/store/host2/tank 49.8G 867G 32K /tank/... tank/store/host2/tank/home 7.39G 867G 6.93G /tank/... tank/store/host2/tank/vm 42.4G 867G 30K /tank/... tank/store/host2/tank/vm/vm1 32.0G 867G 29.7G - tank/store/host2/tank/vm/vm2 10.4G 867G 10.4G - tank/store/host2/rpool 5.12G 867G 32K /tank/... tank/store/host2/rpool/misc 521M 867G 521M /tank/... tank/store/host2/rpool/host2-1 4.61G 867G 33K /tank/... tank/store/host2/rpool/host2-1/ROOT 317M 867G 312M /tank/... tank/store/host2/rpool/host2-1/usr 3.76G 867G 3.76G /tank/... tank/store/host2/rpool/host2-1/var 554M 867G 401M /tank/... .fi .PP I've trimmed the "mountpoint" column here so it doesn't get too wide for the screen. .PP You see here the same 54.9G used as in the previous example, but now you can trace it down. There were two zpools on host2: tank and rpool. Most of the backup space -- 49.8G of the 54.9G -- is used by tank, and only 5.12G by rpool. And in tank, 42.4G is used by vm. Tracing it down, of that 42.4G used by vm, 32G is in vm1 and 10.4G in vm2. Notice how the values at each level of the tree include their descendents. .PP So in this example, vm1 and vm2 are zvols corresponding to virtual machines, and clearly take up a lot of space. Notice how vm1 says it uses 32.0G but in the refer column, it only refers to 29.7G? That means that the latest backup for vm2 used 29.7G, but when you add in the snapshots for that dataset, the total space consumed is 32.0G. .PP Let's look at an alternative view that will make the size consumed by snapshots more clear: .nf # zfs list -o space -r tank/store/host2 NAME AVAIL USED USEDSNAP USEDDS USEDCHILD \&.../host2 867G 54.9G 0 32K 54.9G \&.../host2/tank 867G 49.8G 0 32K 49.8G \&.../host2/tank/home 867G 7.39G 474M 6.93G 0 \&.../host2/tank/vm 867G 42.4G 50K 30K 42.4G \&.../host2/tank/vm/vm1 867G 32.0G 2.35G 29.7G 0 \&.../host2/tank/vm/vm1 867G 10.4G 49K 10.4G 0 \&.../host2/rpool 867G 5.12G 0 32K 5.12G \&.../host2/rpool/misc 867G 521M 51K 521M 0 \&.../host2/rpool/host2-1 867G 4.61G 51K 33K 4.61G \&.../host2/rpool/host2-1/ROOT 867G 317M 5.44M 312M 0 \&.../host2/rpool/host2-1/usr 867G 3.76G 208K 3.76G 0 \&.../host2/rpool/host2-1/var 867G 554M 153M 401M 0 .fi .PP (Again, I've trimmed some irrelevant columns from this output.) .PP The AVAIL and USED columns are the same as before, but now you have a breakdown of what makes up the USED column. USEDSNAP is the space used by the snapshots of that particular dataset. USEDDS is the space used by that dataset directly -- the same value as was in REFER before. And USEDCHILD is the space used by descendents of that dataset. .PP The USEDSNAP column is the easiest way to see the impact your retention policies have on your backup space consumption. .SS "VIEWING SNAPSHOTS OF A DATASET" .PP Let's take one example from before -- the 153M of snapshots in host2-1/var, and see what we can find. .nf # zfs list -t snap -r tank/store/host2/rpool/host2-1/var NAME USED AVAIL REFER \&... \&.../var@host2-hourly-2014-02-11_05.17.02--2d 76K - 402M \&.../var@host2-hourly-2014-02-11_06.17.01--2d 77K - 402M \&.../var@host2-hourly-2014-02-11_07.17.01--2d 18.8M - 402M \&.../var@host2-daily-2014-02-11_07.17.25--1w 79K - 402M \&.../var@host2-hourly-2014-02-11_08.17.01--2d 156K - 402M \&.../var@host2-monthly-2014-02-11_09.01.36--1m 114K - 402M \&... .fi .PP In this output, the REFER column is the amount of data pointed to by that snapshot -- that is, the size of /var at the moment the snapshot is made. And the USED column is the amount of space that would be freed if just that snapshot were deleted. .PP Note this important point: it is normal for the sum of the values in the USED column to be less than the space consumed by the snapshots of the datasets as reported by USEDSNAP in the previous example. The reason is that the USED column is the data unique to that one snapshot. If, for instance, 100MB of data existed on the system being backed up for three hours yesterday, each snapshot could very well show less than 100KB used, because that 100MB isn't unique to a particular snapshot. Until, that is, two of the three snapshots referncing the 100MB data are destroyed; then the USED value of the last one referencing it will suddenly jump to 100MB higher because now it references unique data. .PP One other point -- an indication that the last backup was successfully transmitted is the presence of a __simplesnap_...__ snapshot at the end of the list. Do not delete it. .SS "FINDING WHAT CHANGED OVER TIME" .PP The \fBzfs diff\fR command can let you see what changed over time -- either across a single snapshot, or across many. Let's take a look. .nf # zfs diff .../var@host2-hourly-2014-02-11_05.17.02--2d \\ \&.../var@host2-hourly-2014-02-11_06.17.01--2d \\ | sort -k2 | less M /tank/store/host2/rpool/host2-1/var/log/Xorg.0.log M /tank/store/host2/rpool/host2-1/var/log/auth.log M /tank/store/host2/rpool/host2-1/var/log/daemon.log \&... M /tank/store/host2/rpool/host2-1/var/spool/anacron/cron.daily M /tank/store/host2/rpool/host2-1/var/spool/anacron/cron.monthly M /tank/store/host2/rpool/host2-1/var/spool/anacron/cron.weekly M /tank/store/host2/rpool/host2-1/var/tmp .fi .PP Here you can see why there was just a few KB of changes in that snapshot: mostly just a little bit of logging was happening on the system. Now let's inspect the larger snapshot: .nf # zfs diff .../var@host2-hourly-2014-02-11_07.17.01--2d \\ \&.../var@host2-daily-2014-02-11_07.17.25--1w \\ | sort -k2 | less M /tank/store/host2/rpool/host2-1/var/backups + /tank/store/host2/rpool/host2-1/var/backups/dpkg.status.0 - /tank/store/host2/rpool/host2-1/var/backups/dpkg.status.0 + /tank/store/host2/rpool/host2-1/var/backups/dpkg.status.1.gz R /tank/store/host2/rpool/host2-1/var/backups/dpkg.status.1.gz -> /tank/store/host2/rpool/host2-1/var/backups/dpkg.status.2.gz R /tank/store/host2/rpool/host2-1/var/backups/dpkg.status.2.gz -> /tank/store/host2/rpool/host2-1/var/backups/dpkg.status.3.gz \&... M /tank/store/host2/rpool/host2-1/var/cache/apt R /tank/store/host2/rpool/host2-1/var/cache/apt/pkgcache.bin.KdsMLu -> /tank/store/host2/rpool/host2-1/var/cache/apt/pkgcache.bin .fi .PP Here you can see some file rotation going on, and a temporary file being renamed to permanent. Normal daily activity on a system, but now you know what was taking up space. .SH "WARNINGS, CAUTIONS, AND GOOD PRACTICES" .SS "IMPORTANCE OF TESTING" .PP Any backup scheme should be tested carefully before being relied upon to serve its intended purpose. This item is not \fBsimplesnap\fR-specific, but pertains to every backup solution: test that you are backing up the data you expect to before you need it. .SS "USE OF ZFS RECEIVE -F" .PP In order to account for various situations that could lead to divergence of filesystems, including the simple act of mounting them, \fBsimplesnap\fR always uses \fBzfs receive -F\fR\&. Any local changes you make to the \fBsimplesnap\fR store datasets will be lost at any time. If you need to make local changes there, it is best to copy them elsewhere. .SS "EXTRANEOUS SNAPSHOT BUILDUP" .PP Since \fBsimplesnap\fR sends all snapshots, it is possible that locally-created snapshots made outside of your rotation scheme will also be sent to your backuphost. These may not be automatically reaped there, and may stick around. An example at the end of the \fIcron.daily.simplesnap.backuphost\fR file included with \fBsimplesnap\fR is one way to check for these. They could automatically be reaped with \fBzfs destroy\fR as well, but this must be carefully tuned to local requirements, so an example of doign that is intentionally not supplied with the distribution. .SS "INTERNAL SIMPLESNAP SNAPSHOTS" .PP \fBsimplesnap\fR creates snapshots beginning with __simplesnap_ followed by your \fISETNAME\fR\&. Do not create, remove, or alter these snapshots in any way, either on the activehost or the backuphost. Doing so may lead to unpredictable side-effects. .SH "BUGS" .PP Ordinarily, an interrupted transfer is no problem for \fBsimplesnap\fR\&. However, the very first transfer of a dataset poses a bit of a problem, since the \fBsimplesnap\fR wrapper can't detect failure in this one special case. If your first transfer gets interrupted, simply zfs destroy the __simplesnap_...__ snapshot on the activehost and rerun. NEVER DESTROY __simplesnap SNAPSHOTS IN ANY OTHER SITUATION! .SH "SEE ALSO" .PP zfSnap (1), zfs (8). .PP The \fBsimplesnap\fR homepage: .PP The examples included with the \fBsimplesnap\fR distribution, or on its homepage. .PP The zfSnap package compliments \fBsimplesnap\fR perfectly. Find it at \&. .SH "AUTHOR" .PP This software and manual page was written by John Goerzen \&. Permission is granted to copy, distribute and/or modify this document under the terms of the GNU General Public License, Version 3 any later version published by the Free Software Foundation. The complete text of the GNU General Public License is included in the file COPYING in the source distribution. simplesnap-1.0.3/doc/Makefile0000644000000000000000000000041012276501225012756 0ustar all: simplesnap.8 simplesnap.html simplesnap.8: simplesnap.sgml docbook2man simplesnap.sgml docbook2man simplesnap.sgml docbook2man simplesnap.sgml simplesnap.html: simplesnap.sgml docbook2html -u simplesnap.sgml clean: rm -f simplesnap.html simplesnap.8 simplesnap-1.0.3/doc/manpage.refs0000644000000000000000000000003312277151521013611 0ustar { '' => '', '' => '' }