On Aug 13, 2012, at 2:24 AM, Sašo Kiselkov wrote:
> On 08/13/2012 10:45 AM, Scott wrote:
>> Hi Saso,
>> thanks for your reply.
>> If all disks are the same, is the root pointer the same?
>> Also, is there a "signature" or something unique to the root block that I can
>> search for on the disk? I'm going through the On-disk specification at the
> Nope. The checksums are part of the blockpointer, and the root
> blockpointer is in the uberblock, which itself resides in the label. By
> overwriting the label you've essentially erased all hope of practically
> finding the root of the filesystem tree - not even checksumming all
> possible block combinations (of which there are quite a few) will help
> you here, because you have no checksums to compare them against.
> I'd love to be wrong, and I might be (I don't have as intimate a
> knowledge of ZFS' on-disk structure as I'd like), but from where I'm
> standing, your raidz vdev is essentially lost.
The labels are not identical, because each contains the guid for the device.
It is possible, though nontrivial, to recreate.
That said, I've never seen a failure that just takes out only the ZFS labels.
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