Using ZFS as RAID0 - disk offline question

[Johan Hendriks]

Kaya Saman schreef:
> On 06/04/2012 09:17 PM, Matthew Seaman wrote:
>> On 04/06/2012 21:00, Kaya Saman wrote:
>>> in ZFS when using a simple RAID 0 style array is there a way to recover
>>> a pool after a disk has gone down?
>> No.  RAID0 has no resilience to disk failure.  That's why things like
>> RAID1, RAID10, RAIDz, RAIDz2 exist: so that your data will survive
>> failure of some number of the drives it is stored on.
>>
>> Make sure you have good backups, basically.
>>
>>     Cheers
>>
>>     Matthew
>>
>
> Thanks for the responses!
>
>
> I wasn't actually meaning recovering data on the 'downed' disk but on 
> the disk that was still online......
>
>
> 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?
>
>
> 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??
>
>
> This is what I was trying to get at and sorry if I didn't understand 
> 100% the direction of the responses!
>
> As in if you meant that the information of on /dev/ad5 will be lost - 
> I do understand this :-)
>
>
> Regards,
>
> Kaya
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you can not loose a disk from a raid0 period.
To put it simple, your files are split in half, one part is copied to 
disk 1 and the other part on disk2 .
So without the two copies no files, no data.

If device names changes because of a hardware change, the pool schould 
be importable.
But both disks need to be there.
Raid0 should be avoided if possible, better add one disk extra and 
create a raidz.

regards
Johan Hendriks