comprehensive backup solution for ZFS

[carcrusher]

Hi!
First of all I want to thank for replies to my post about zfs recovery tool and clarifying some basic aspects of it.
According to this post I want to ask some questions about making reliable copy/backup/sync of FreeNAS resources:

1. Is there any rational reason for making such backup to non-ZFS drive if we need 100% confidence that our data are safe? We spend a lot of money on FreeNAS-box. But what if the backup is on NTFS/EXT? Those data can get corrupted without our knowledge, and when the FreeNAS-box fails we recreate it with corrupted data...
2. If the answer for first question is "no" or sht like "every backup is better than none" : What about making an offline backup of mirrored ZFS drives to a single one ZFS drive? Is such solution safe? I assume that if we have mirrored data and part of them (with the checksums also) - just on one HDD - gets corrupted, ZFS would check the mirrored files and if the data/checksum are good it will replace the bad ones. Am I right? But what if we have just one drive without any redundancy? Is ZFS in such case any better than other FS (in terms of "data protection")?
3. I know that plugging in and out disks into FreeNAS is not a good idea (although it was my first thought about easy offline backup). So I understand that I need a second machine with ECC-RAM... (I wonder if I would be able to explain it to my wife) Sadly I can't afford a second 1k$ machine just for backups... But what if I could use it as a standard PC with optional USB/CD booting into FreeBSD/ZFSonLinux/nexenta (and plugging in backup storage)? Is it a good idea? Is there any advantage on using FreeBSD system over linux or nexenta for that purpose?
4. Would it be better to copy the data over RSYNC or ZFS replication? Which is faster?

thanks in advance for replies!
BTW: I don't agree that most of people use FreeNAS for storing torrents

 

[cyberjock]

1. Absolutely correct. That's why 99% of people do backups to zpools. ;)
2. Every backup is better than non though. Going with single disk ZFS is as safe as anything else out there. If there is corruption ZFS will know about it, but will be unable to fix it. If you were using NTFS or EXT you'd have never known about the corruption.
3. The general rule is that a second system that is reliable and using ZFS is better. FreeNAS works "best" with itself since the manual gives clear instructions for setting that up. If you want to use Linux or Nexenta you can. You're just on your own to figure out how to implement it.
4. zfs replication is FARRRRRR faster. There's no competition at all.

 

[L]

The one thing that no one can help with is, if the client writes bad data.. But with snapshots, you can keep many more copies so you can try to go back and find a good copy of a single file.