commit 7432ad423080adab32c9ee0321b4c2e912897465
parent 741745cffa3b6554999150ff0928a5c663428638
Author: Christos Margiolis <christos@margiolis.net>
Date: Sun, 3 Apr 2022 22:37:20 +0300
handle snap renewal better
Diffstat:
| M | backup | | | 43 | +++++++++++++++++++++++++++++++------------ |
1 file changed, 31 insertions(+), 12 deletions(-)
diff --git a/backup b/backup
@@ -2,21 +2,34 @@
usage()
{
- echo "usage: ${0##*/} [-i] <from> <to>" 1>&2
+ echo "usage: ${0##*/} [-ir] <src> <dst>" 1>&2
+ exit 1
+}
+
+err()
+{
+ echo "${0##*/}: ${@}" 1>&2
exit 1
}
pool_exists()
{
local foo=$(zpool list | sed 1d | awk '{print $1}' | grep -x "${1}")
- test -z "${foo}" && echo "${0##*/}: pool ${1} does not exist" && exit 1
-}
+ test -z "${foo}" && err "pool ${1} does not exist"
+}
-f_incr=0
+last_snap()
+{
+ zfs list -t snapshot -o name "${1}" | cut -f2 -d'@' | tail -1
+}
+
+f_incr=0 # Incremental backup
+f_snap=0 # Renew snapshots in case they already exist
-while getopts i arg; do
+while getopts ir arg; do
case "${arg}" in
i) f_incr=1 ;;
+ r) f_snap=1 ;;
*) usage ;;
esac
done
@@ -31,17 +44,23 @@ pool_exists "${src_pool}"
pool_exists "${dst_pool}"
new_snap="$(date +%Y%m%d)"
-last_snap="$(zfs list -t snapshot -o name ${dst_pool} | cut -f2 -d'@' | tail -1)"
+dst_last_snap=$(last_snap "${dst_pool}")
nsnaps=$(zfs list -t snapshot -o name ${dst_pool} | sed 1d | wc -l)
-# make sure we don't have a snapshot already
-# also don't delete in case there's only one snap, otherwise we'll lose it all
-if [ ! ${nsnaps} -le 1 ] && [ "${last_snap}" = "${new_snap}" ]; then
+# Overwrite snapshot if it already exists when the -r option is passed,
+# otherwise, exit. Also make sure there are more than 1 snapshots before we
+# delete anything.
+if [ ! ${nsnaps} -le 1 ] && [ "${dst_last_snap}" = "${new_snap}" ]; then
+ test ${f_snap} -eq 1 || err "snapshot ${new_snap} exists already"
zfs destroy -r ${dst_pool}@${new_snap}
fi
-# create new snapshot in case we had made one already today
-zfs destroy -r ${src_pool}@${new_snap}
-zfs snapshot -r ${src_pool}@${new_snap}
+
+# Create new src snapshots when the -r option is passed.
+if [ ${f_snap} -eq 1 ]; then
+ zfs destroy -r ${src_pool}@${new_snap}
+ zfs snapshot -r ${src_pool}@${new_snap}
+fi
+
if [ ${f_incr} -eq 1 ]; then
zfs send -RI ${src_pool}@${last_snap} ${src_pool}@${new_snap} | pv | zfs recv -Fu ${dst_pool}
else
