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

[Volodymyr Kostyrko]

On 22.04.2010 17:41, Martin Simmons wrote:
> When I attach a second disk to a single-disk zpool to make a mirrored pool,
> the original disk is partially resilvered.  Is that expected?  It makes me
> worry that some of the good data is being overwritten.
 >
> 	NAME             STATE     READ WRITE CKSUM
> 	ztest            ONLINE       0     0     0
> 	  mirror         ONLINE       0     0     0
> 	    /tmp/zdisk0  ONLINE       0     0     0  86K resilvered
> 	    /tmp/zdisk1  ONLINE       0     0     0  16.1M resilvered
>
> errors: No known data errors

1. ZFS tries to store checksums as far as it can. Another drive preferrably.
2. ZFS tries to store metadata copies in different location as far as it 
can.

-- 
Sphinx of black quartz judge my vow.