I want to provide protection against data loss on my servers.

Typically, I'd use hardware RAID 1 or 5, but I've been reading up on ZFS.

Is it correct that ZFS itself provides RAID 1 or 5 like data protection WITHOUT needing a RAID controller card?

If so, I assume a single hard drive is not enough to provide data protection since if that drive fails, all data fails, so how many hard drives do I need to be running for ZFS to provide this protection?


Yes, ZFS doesn't need hardware raid and is actually better when used without it.

It is able to provide partial data protection even with a single device when configured to use ditto blocks but of course won't resist a full disk failure in that case.

You can use it in a mirror configuration (two devices or more) or a RAIDZ one (three devices or more) to survive failures. RAID-Z2 and RAID-Z3 provide 2 and 3 concurrent device failures protection.

| improve this answer | |
  • +1 It's highly recommend to not use a Hardware RAID controller with ZFS. – Chris S Jun 7 '12 at 15:48
  • How well does that scale? Saying to a little small 4U case with 72 disc slots? – TomTom Jun 7 '12 at 16:27
  • @TomTom That depends on how you organize your pool(s) which itself depends on your goals. – jlliagre Jun 7 '12 at 22:14
  • @TomTom - also depends on how much RAM is in the system. ZFS is pretty memory hungry. Also be wary of heat if you have 72 disks in a 4U chassis. – ghoti Jun 27 '12 at 12:31
  • 1
    Hardly. Check SuperMicro - they offer those cases and they are perfectly fine heat wise ;) THis is not a hommade solution, it is pretty much an enterprise component. I currently use 22 discs for storage and they approach a too alrge fill factor. – TomTom Jun 27 '12 at 12:35

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.