zfs-backup/zb-cleanup

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#!/bin/bash
source /etc/profile >/dev/null
[ -f "$HOME/.zb-rc" ] && source "$HOME/.zb-rc"
if [[ -z "$1" || -z "$2" ]] ; then
echo "usage: $0 <zfs_object> <density_percent> [max_age]" >&2
exit 1
fi
if [[ "$2" -lt 100 ]] ; then
echo "density must be >= 100" >&2
exit 2
fi
timestamp () {
t="`echo \"$1\" |sed -ne 's/^.*@zb-//p' |tr 'p_' '+ '`"
[[ -z "$t" ]] && return 1
date --date="$t" +%s
return $?
}
max_age=0
if [[ -n "$3" ]] ; then
max_age=`date --date="$3" +%s`
fi
density="$2"
timenow=`date +%s`
lasttime=0
# list snapshots
zfs list -t snapshot -r -d 1 -H "$1" |awk '{print $1;}' | while read l ; do
#link unix timestamps
unixtime=`timestamp "$l"` || continue
echo "$unixtime" "$l"
done |sort -n | while read l ; do
curtime=${l%% *}
snapname=${l#* }
if [ "$curtime" -lt "$max_age" ] ; then
#too old
zfs destroy "$snapname" || echo "$0: zfs destroy $snapname failed" >&2
continue
fi
if [ "$curtime" -ge "$timenow" ] ; then
#this actually shouldn't happen, but who knows
break
fi
#if it's too dense, delete the closer snapshot
if [ $(( ($density*($curtime-$lasttime))/($timenow-$lasttime) )) -lt 100 ]
then
zfs destroy "$snapname" || echo "$0: zfs destroy $snapname failed" >&2
else
lasttime="$curtime"
fi
done