Problems replacing failing drive in ZFS pool

Clifton Royston cliftonr at
Tue Jul 20 01:25:44 UTC 2010

On Mon, Jul 19, 2010 at 06:28:16PM -0400, Garrett Moore wrote:
> Well thank you very much Western Digital for your absolutely pathetic RMA
> service sending me an inferior drive. I'll call tomorrow and see what can be
> done; I'm going to insist on these 00R6B0 drives being sent back, and being
> given a drive of >= 1,500,301,910,016 bytes capacity.
> At least now I learned how to hotswap :/

This is the wrong time to find it out, I know, but:

For geom mirror purposes I have taken to carving out HD partitions
which are exactly a round number of GiB, and at least 100 MiB less than
the claimed capacity.  I then label the partitions using geom label,
and use the partition label specification in setting up the mirror.

The first means that when an unannounced change in drive capacity like
this happens, I can still add the smaller drive into a RAID set of
larger drives painlessly, because the partition sizes will still match
exactly.  (It also means that if I can only find a larger drive, e.g.
if 1TB drives later drop off the market or are more expensive than
larger drives, I can easily add a larger drive into the set by making
its partition size match the rest.)

The second means that if the BIOS/probing sequence does its little
dance and the drives end up getting renumbered, it does not affect
which drive is which part of what mirror in the slightest.

The space sacrificed is trivial compared to the convenience and safety

I think I got both those suggestions on this list, and I would hope
(assume?) that they have equivalents under ZFS. 

  -- Clifton

    Clifton Royston  --  cliftonr at / cliftonr at
       President  - I and I Computing *
 Custom programming, network design, systems and network consulting services

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