I am considering migrating from (debian + mirrored raid + daily differential backups + weekly full backups) to ZFS raidz. Is there any point of performing backups in ZFS the same way as my current setup? To my understanding snapshots provides full filesystem history and backups are only needed for more security. In case of emergency I allways keep weekly full backup on external drive.
If you schedule your snaps weekly, you will be fairly close to your previous setup. If you bomb out completely you will not recover any snapshots since your last weekly. I would recommend getting familiar with the zfs send/receive commands. Very powerful stuff. I send zfs streams all over the place: file, other zfs pools, other zfs hosts, cloud, etc. Love the zfs
There's a lot of questions here. How are you doing back ups now? To tape? To another local disk? Offsite?
ZFS works best (depending on your interpretation of "best") with mirrored pairs (i.e., striped mirrors, aka RAID 10), adding mirrored pairs to your zpool whenever you need more space. RAIDZ has some severe performance problems under some workloads.
If your back up strategy is just to copy to another local disk then just go with ZFS mirroring instead.
If your back up strategy is something else, do a
If you're going to use Solaris 11 or OpenIndiana look into the