Daily sync SSD data to HDD for backup (or any other local zfs pools)

zfs_hdd_sync_backup.sh

#!/bin/sh

SRC="z"
DST="backup"

DATE=$(date +%Y-%m-%d)

### For first time run:
# zfs snapshot -r ${SRC}@${DATE} || (echo "Fail to create ${SRC}@${DATE}"; exit 1)
# zfs send -R ${SRC}@${DATE} | zfs recv -F ${DST}
# exit 0

echo "Today: ${DATE}"

LAST_SNAPSHOT=$(zfs list -Hd1 -t snapshot -o name ${DST} | grep -e '[[:digit:]]\{4\}-[[:digit:]]\{2\}-[[:digit:]]\{2\}' | sed 's/.*@//' | sort | tail -n1)

echo "Transfer snapshots between ${LAST_SNAPSHOT} and ${DATE}"

if [ "${LAST_SNAPSHOT}" == "${DATE}" ]; then
        echo "Already have target snapshot ${DST}@${DATE}";
        exit 0;
fi


echo -n "Creating snapshot ${SRC}@${DATE} ... "
zfs snapshot -r ${SRC}@${DATE} || (echo "Fail to create ${SRC}@${DATE}"; exit 1)
echo "Done."

echo -n "Sending snapshots from ${LAST_SNAPSHOT} to ${DATE} ... "
(zfs send -Ri ${LAST_SNAPSHOT} ${SRC}@${DATE} | zfs receive ${DST}) || (echo "Fail to send/receive snapshots."; exit 1)
echo "Done."