mirror of
https://github.com/nachoparker/btrfs-sync
synced 2024-04-30 06:35:09 +02:00
249 lines
8.4 KiB
Bash
Executable File
249 lines
8.4 KiB
Bash
Executable File
#!/bin/bash
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#
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# Simple script that synchronizes BTRFS snapshots locally or through SSH.
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# Features compression, retention policy and automatic incremental sync
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#
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# Usage:
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# btrfs-sync [options] <src> [<src>...] [[user@]host:]<dir>
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#
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# -k|--keep NUM keep only last <NUM> sync'ed snapshots
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# -d|--delete delete snapshots in <dst> that don't exist in <src>
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# -z|--xz use xz compression. Saves bandwidth, but uses one CPU
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# -Z|--pbzip2 use pbzip2 compression. Saves bandwidth, but uses all CPUs
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# -q|--quiet don't display progress
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# -v|--verbose display more information
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# -h|--help show usage
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#
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# <src> can either be a single snapshot, or a folder containing snapshots
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# <user> requires privileged permissions at <host> for the 'btrfs' command
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#
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# Cron example: daily synchronization over the internet, keep only last 50
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#
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# cat > /etc/cron.daily/btrfs-sync <<EOF
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# #!/bin/bash
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# /usr/local/sbin/btrfs-sync -q -k50 -z /home user@host:/path/to/snaps
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# EOF
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# chmod +x /etc/cron.daily/btrfs-sync
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#
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# Copyleft 2018 by Ignacio Nunez Hernanz <nacho _a_t_ ownyourbits _d_o_t_ com>
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# GPL licensed (see end of file) * Use at your own risk!
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#
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# More at https://ownyourbits.com
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#
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# help
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print_usage() {
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echo "Usage:
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$BIN [options] <src> [<src>...] [[user@]host:]<dir>
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-k|--keep NUM keep only last <NUM> sync'ed snapshots
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-d|--delete delete snapshots in <dst> that don't exist in <src>
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-z|--xz use xz compression. Saves bandwidth, but uses one CPU
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-Z|--pbzip2 use pbzip2 compression. Saves bandwidth, but uses all CPUs
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-q|--quiet don't display progress
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-v|--verbose display more information
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-h|--help show usage
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<src> can either be a single snapshot, or a folder containing snapshots
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<user> requires privileged permissions at <host> for the 'btrfs' command
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Cron example: daily synchronization over the internet, keep only last 50
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cat > /etc/cron.daily/btrfs-sync <<EOF
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#!/bin/bash
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/usr/local/sbin/btrfs-sync -q -k50 -z /home user@host:/path/to/snaps
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EOF
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chmod +x /etc/cron.daily/btrfs-sync
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"
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}
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echov() { [[ "$VERBOSE" == 1 ]] && echo "$@" || true; }
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#----------------------------------------------------------------------------------------------------------
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# parse arguments
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BIN="${0##*/}"
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KEEP=0
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ZIP=cat PIZ=cat
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SILENT=">/dev/null"
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OPTS=$( getopt -o hqzZk:dv -l quiet -l help -l xz -l pbzip2 -l keep: -l delete -l verbose -- "$@" 2>/dev/null )
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[[ $? -ne 0 ]] && { echo "error parsing arguments"; exit 1; }
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eval set -- "$OPTS"
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while true; do
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case "$1" in
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-h|--help ) print_usage; exit 0 ;;
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-q|--quiet ) QUIET=1 ; shift 1 ;;
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-d|--delete ) DELETE=1 ; shift 1 ;;
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-k|--keep ) KEEP=$2 ; shift 2 ;;
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-z|--xz ) ZIP=xz PIZ=( xz -d ); shift 1 ;;
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-Z|--pbzip2 ) ZIP=pbzip2 PIZ=( pbzip2 -d ); shift 1 ;;
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-v|--verbose) SILENT="" VERBOSE=1 ; shift 1 ;;
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--) shift; break ;;
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esac
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done
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SRC=( "${@:1:$#-1}" )
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DST="${@: -1}"
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# detect remote dst argument
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[[ "$DST" =~ : ]] && {
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NET="$( sed 's|:.*||' <<<"$DST" )"
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DST="$( sed 's|.*:||' <<<"$DST" )"
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SSH=( ssh -o ServerAliveInterval=5 -o ConnectTimeout=1 "$NET" )
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}
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[[ "$SSH" != "" ]] && DST_CMD=( ${SSH[@]} ) || DST_CMD=( eval )
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#----------------------------------------------------------------------------------------------------------
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# checks
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## general checks
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[[ $# -lt 2 ]] && { print_usage ; exit 1; }
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[[ ${EUID} -ne 0 ]] && { echo "Must be run as root. Try 'sudo $BIN'"; exit 1; }
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${DST_CMD[@]} true &>/dev/null || { echo "SSH access error to $NET" ; exit 1; }
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## src checks
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for s in "${SRC[@]}"; do
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src="$(cd "$s" &>/dev/null && pwd)" || { echo "$s not found"; exit 1; } #abspath
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btrfs subvolume show "$src" &>/dev/null && SRCS+=( "$src" ) || \
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for dir in $( ls -drt "$src"/* 2>/dev/null ); do
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btrfs subvolume show "$dir" &>/dev/null && SRCS+=( "$dir" )
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done
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done
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[[ ${#SRCS[@]} -eq 0 ]] && { echo "no BTRFS subvolumes found"; exit 1; }
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## check pbzip2
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[[ "$ZIP" == "pbzip2" ]] && {
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type pbzip2 &>/dev/null && \
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"${DST_CMD[@]}" type pbzip2 &>/dev/null || {
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echo "INFO: 'pbzip2' not installed on both ends, fallback to 'xz'"
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ZIP=xz PIZ=unxz
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}
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}
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## use 'pv' command if available
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PV=( pv -F"time elapsed [%t] | rate %r | total size [%b]" )
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[[ "$QUIET" == "1" ]] && PV=( cat ) || type pv &>/dev/null || {
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echo "INFO: install the 'pv' package in order to get a progress indicator"
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PV=( cat )
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}
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#----------------------------------------------------------------------------------------------------------
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# sync snapshots
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## get dst snapshots ( DSTS, DST_UUIDS )
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get_dst_snapshots() {
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local DST="$1"
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unset DSTS DST_UUIDS
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while read entry; do
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DST_UUIDS+=( "$( sed 's=|.*==' <<<"$entry" )" )
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DSTS+=( "$( sed 's=.*|==' <<<"$entry" )" )
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done < <(
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"${DST_CMD[@]}" "
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DSTS=( \$( ls -d \"$DST\"/* 2>/dev/null ) )
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for dst in \${DSTS[@]}; do
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UUID=\$( sudo btrfs su sh \"\$dst\" 2>/dev/null | grep 'Received UUID' | awk '{ print \$3 }' )
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[[ \"\$UUID\" == \"-\" ]] || [[ \"\$UUID\" == \"\" ]] && continue
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echo \"\$UUID|\$dst\"
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done"
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)
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}
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## sync incrementally
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sync_snapshot() {
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local SRC="$1"
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local ID LIST PATH_ DATE SECS SEEDS SEED SEED_PATH SEED_ARG
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# detect existing
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SRC_UUID=$( btrfs su sh "$SRC" | grep "UUID:" | head -1 | awk '{ print $2 }' )
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for id in "${DST_UUIDS[@]}"; do
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[[ "$SRC_UUID" == "$id" ]] && { echov "* Skip existing '$SRC'"; return 0; }
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done
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# try to get most recent src snapshot that exists in dst to use as a seed
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LIST="$( btrfs subvolume list -su "$SRC" )"
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for id in "${DST_UUIDS[@]}"; do
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ID=$(btrfs su sh -u "$id" "$SRC" 2>/dev/null|grep "UUID:"|head -1|awk '{print $2}')
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PATH_=$( awk "{ if ( \$14 == \"$ID\" ) print \$16 }" <<<"$LIST" )
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DATE=$( awk "{ if ( \$14 == \"$ID\" ) print \$11, \$12 }" <<<"$LIST" )
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[[ "$ID" == "" ]] || [[ "$PATH_" == "$( basename "$SRC" )" ]] && continue
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SECS=$( date -d "$DATE" +"%s" )
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SEEDS+=( "$SECS|$PATH_" )
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done
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SEED="$(for s in "${SEEDS[@]}";do echo "$s";done|sort -V|tail -1|cut -f2 -d'|')"
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# incremental sync argument
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[[ "$SEED" != "" ]] && {
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SEED_PATH="$( dirname "$SRC" )/$( basename $SEED )"
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[[ -d "$SEED_PATH" ]] &&
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SEED_ARG=( -p "$SEED_PATH" ) || \
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echo "INFO: couldn't find $SEED_PATH. Non-incremental mode"
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}
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# do it
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echo -n "* Synchronizing '$src'"
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[[ "$SEED_ARG" != "" ]] && echov -n " using seed '$SEED'"
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echo "..."
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{ btrfs send -q ${SEED_ARG[@]} "$SRC" \
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| "$ZIP" \
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| "${PV[@]}" \
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| "${DST_CMD[@]}" "${PIZ[@]} | sudo btrfs receive \"$DST\" 2>&1 | grep -v '^At subvol '" \
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|| exit 1; } | grep -v "^At snapshot "
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get_dst_snapshots "$DST" # sets DSTS DST_UUIDS
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}
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#----------------------------------------------------------------------------------------------------------
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# sync all snapshots found in src
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get_dst_snapshots "$DST" # sets DSTS DST_UUIDS
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for src in "${SRCS[@]}"; do
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sync_snapshot "$src"
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done
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#----------------------------------------------------------------------------------------------------------
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# retention policy
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[[ "$KEEP" != 0 ]] && \
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[[ ${#DSTS[@]} -gt $KEEP ]] && \
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echov "* Pruning old snapshots..." && \
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for (( i=0; i < $(( ${#DSTS[@]} - KEEP )); i++ )); do
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PRUNE_LIST+=( "${DSTS[$i]}" )
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done && \
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${DST_CMD[@]} sudo btrfs subvolume delete "${PRUNE_LIST[@]}" $SILENT
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# delete flag
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[[ "$DELETE" == 1 ]] && \
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for dst in "${DSTS[@]}"; do
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FOUND=0
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for src in "${SRCS[@]}"; do
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[[ "$( basename $src )" == "$( basename $dst )" ]] && { FOUND=1; break; }
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done
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[[ "$FOUND" == 0 ]] && DEL_LIST+=( "$dst" )
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done
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[[ "$DEL_LIST" != "" ]] && \
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echov "* Deleting non existent snapshots..." && \
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${DST_CMD[@]} sudo btrfs subvolume delete "${DEL_LIST[@]}" $SILENT
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# License
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#
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# This script is free software; you can redistribute it and/or modify it
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# under the terms of the GNU General Public License as published by
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# the Free Software Foundation; either version 2 of the License, or
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# (at your option) any later version.
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#
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# This script is distributed in the hope that it will be useful,
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# but WITHOUT ANY WARRANTY; without even the implied warranty of
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# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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# GNU General Public License for more details.
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#
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# You should have received a copy of the GNU General Public License
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# along with this script; if not, write to the
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# Free Software Foundation, Inc., 59 Temple Place, Suite 330,
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