Using ZFS as RAID0 - disk offline question

[Kaya Saman]

On 06/04/2012 09:38 PM, Matthew Seaman wrote:
> On 04/06/2012 21:26, Kaya Saman wrote:
>> You see if say a system board fails and both devices are named /dev/ad4
>> and /dev/ad5 then a new system board gets put in and the device names
>> changed to /dev/ad12 and /dev/ad13 my question is will the ZPOOL still
>> exist? Will ZFS be intelligent enough to pick up the new device names
>> via the disk ID's?
> Yes, this should work just fine.  ZFS labels each disk with its own UUID
> value, so you can pretty much shuffle the disks in any order across all
> available disk slots, and ZFS will be able to put the zpool back together.
>
>> Additionally if /dev/ad5 goes down, is it possible to keep using
>> /dev/ad4 which is part of the 'downed' pool...?? Or would one need to
>> replace the disk ad5 then the pool comes up again with only the
>> information on ad4??
> No.  A RAID0 zpool will be marked offline if any of the drives within it
> fails.  You might be able to recover some data from remaining drives,
> but not easily.  The surest way of getting anything back would be to go
> to a specialist disaster recovery company, but expect to pay $$$ for it.
>   Considering the price of hard drives nowadays, this would be a dumb
> choice: you could easily convert your RAID0 to a RAID10 for much less
> than it would cost you to try and recover from a broken RAID0.
>
> Even if you do install a replacement disk, ZFS won't be able to rebuild
> from your original drive.  You'ld have to wipe and rebuild from scratch.
>
> 	Cheers,
>
> 	Matthew
>

Many thanks!

They were exactly the answers I was looking for :-)


Apologies for my inexperience in this matter!


Regards,


Kaya