zfs-snapshot

zfs-znapshot

#!/bin/bash
# Keep a number of snapshots
# adapted from my `backup-zfs`

PREFIX="daily"
KEEP=31	# days
SOURCE="data3"
# non-recursive:
EXCLUDES=("$SOURCE/Temp" "$SOURCE/Temp/playground" "$SOURCE/tmp")

# Sanity check
if ! /sbin/zpool list -o name "$SOURCE" &>/dev/null; then
	echo "$0: Source pool $SOURCE not found, aborting!"
	exit 1
fi

# Generate fs list
fslist=()
while read fs; do
	# Skip excluded fs
	# NOTE: will also skip deletion of old snapshots for this fs
	for e in ${EXCLUDES[@]}; do
		if [[ "$fs" == "$e" ]]; then
			continue 2
		fi
	done

	fslist+=("$fs")
done <<< $(/sbin/zfs list -H -o name -t filesystem,volume -r "$SOURCE")

# Create snapshot
newsnap="${PREFIX}_$(date '+%Y-%m-%d')"
/sbin/zfs snapshot "${fslist[@]/%/@$newsnap}" || exit 1

destroy=()
for fs in "${fslist[@]}"; do
	# Generate list of snapshots
	snaps=()
	while IFS='@' read junk snap; do
		[[ "$snap" =~ "${PREFIX}"_[0-9-]+$ ]] && snaps+=("$snap")
	done <<< "$(/sbin/zfs list -H -o name -t snapshot -s creation "$fs" 2>/dev/null)"

	# Generate list of old snapshots to destroy, keeping $KEEP most recent (reverse order because faster)
	destroy_snaps=""
	for (( i=$(( ${#snaps[@]}-1 - $KEEP )); i>=0; i-- )); do
		destroy_snaps+="${snaps[$i]},"	# only snapshot names can be comma-separated
	done
	[[ "$destroy_snaps" ]] && destroy+=("$fs@$destroy_snaps")
done

# Execute destruction
if [[ "${destroy[@]}" ]]; then
	for d in "${destroy[@]}"; do
		/sbin/zfs destroy "$d" >/dev/null || exit 1
	done
fi