zfs: unexpected resilver of old disk when attaching a new mirror disk

[Martin Simmons]

>>>>> On Thu, 22 Apr 2010 17:11:06 +0200, Adam Nowacki said:
> 
> My best guess is metadata updates to refer to the 2nd disk. I've seen 
> same behavior when replacing a bad disk in 10 disk raidz2 pool. No data 
> was affected.

I would expect all new writes to automatically go to all disks though, so they
wouldn't be counted as resilvering.

__Martin