mirror of
https://github.com/bashclub/bashclub-zfs-push-pull.git
synced 2024-12-24 13:40:13 +01:00
156 lines
3.7 KiB
Bash
Executable File
156 lines
3.7 KiB
Bash
Executable File
#!/bin/bash
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# backup-zfs: use zfs send/recv to push/pull snapshots
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prog="$(basename "$0")"
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usage() {
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cat >&2 <<-EOF
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usage: $prog [-hvq] [-t tag] [-k keep] [-d dateopts] src dest
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use zfs send/recv to push/pull snapshots
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src the source fs, specified as [host:]pool/path/to/fs
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dest the destination fs parent, specified as [host:]pool/path/to/fs
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(the final path component of src will be appended to dest)
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-h help
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-v verbose mode
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-q quiet mode
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-t tag tag to use for naming snapshots (default: backup-zfs)
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-k keep number of snapshots to keep on src (default: 5)
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-d dateopts options for date(1) - used to name the snapshots (default: +%F_%T)
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EOF
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exit $1
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}
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# log to syslog; if verbose or on a tty, also to stdout
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# usage: log msg
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log() {
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logger -t "$prog" -- "$@"
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if ! $quiet && [[ -t 1 ]] || $verbose ; then
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echo "$@" >&2
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fi
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}
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# exit with a code & message
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# usage: die $exitcode msg
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die() {
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code="$1"
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shift
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if [[ $code -ne 0 ]] ; then
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verbose=true log "FATAL: $@"
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else
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log "$@"
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fi
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exit $code
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}
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# run zfs(1) command either locally or via ssh
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# usage: ZFS "$host" command args...
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ZFS() {
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host="$1"
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shift
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if [[ -n $host ]] ; then
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log "remote ($host): zfs $@"
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ssh "$host" sudo zfs "$@"
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else
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log "local: zfs $@"
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sudo zfs "$@"
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fi
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}
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###
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### defaults
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###
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tag="$prog"
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dateopts="+%F_%T"
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keep=5
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verbose=false
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quiet=false
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###
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### parse options
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###
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while getopts "hvqk:t:d:" opt ; do
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case $opt in
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h) usage 0 ;;
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v)
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verbose=true
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send_opts="-v"
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recv_opts="-v"
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;;
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q) quiet=true ;;
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k) keep=$OPTARG ;;
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t) tag=$OPTARG ;;
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d) dateopts=$OPTARG ;;
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*) usage 1 ;;
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esac
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done
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shift $((OPTIND-1))
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date="$(date $dateopts)"
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###
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### parse src & dest host/fs info
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###
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# fail if there's ever >1 colon
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if [[ $1 =~ :.*: || $2 =~ :.*: ]] ; then
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die 1 "invalid fsspec: '$1' or '$2'"
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fi
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# fail if src or dest isn't specified
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if [[ -z $1 || -z $2 ]] ; then
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usage 1
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fi
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src="$1"
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dest="$2"
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# discard anything before a colon to get the fs
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srcfs="${src#*:}"
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destfs="${dest#*:}"
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# iff there is a colon, discard everything after it to get the host
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[[ $src =~ : ]] && srchost="${src%:*}"
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[[ $dest =~ : ]] && desthost="${dest%:*}"
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# get the last src component
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srcbase="${srcfs##*/}"
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# ensure the destination fs exists before proceeding
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if [[ $(ZFS "$desthost" list -H -o name "$destfs" 2>/dev/null) != $destfs ]] ; then
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die 1 "destination fs '$destfs' doesn't exist"
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fi
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###
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### create new snapshot on src
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###
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cur="$srcfs@${tag}_$date"
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ZFS "$srchost" snapshot -r "$cur" || die $? "zfs snapshot failed"
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###
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### get newest snapshot on dest - it must exist on src
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###
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last="$(ZFS "$desthost" list -d 1 -t snapshot -H -S creation -o name $destfs/$srcbase | head -n1 | cut -f2 -d@)"
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###
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### send & receive
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###
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# 1st time: send full snapshot
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if [[ -z $last ]] ; then
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log "sending full recursive snapshot from $src to $dest"
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ZFS "$srchost" send $send_opts -R "$cur" | ZFS "$desthost" receive $recv_opts -Fue "$destfs" || die $? "zfs full send failed"
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# special case: tagged snapshots exist on dest, but src has rotated through all
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elif ! ZFS "$srchost" list $srcfs@$last &>/dev/null ; then
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die 1 "no incremental path from from $src to $dest"
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# normal case: send incremental
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else
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log "sending incremental snapshot from $src to $dest (${last#${tag}_}..${cur#*@${tag}_})"
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ZFS "$srchost" send $send_opts -R -I "$last" "$cur" | ZFS "$desthost" receive $recv_opts -Fue "$destfs" || die $? "zfs incremental send failed"
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fi
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###
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### clean up old snapshots
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###
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for snap in $(ZFS "$srchost" list -d 1 -t snapshot -H -S creation -o name $srcfs \
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| grep -F "@${tag}_" | cut -f2 -d@ | tail -n+$((keep+1)) ) ;
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do
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ZFS "$srchost" destroy -r $srcfs@$snap
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done
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