ZFS zpool mirror drive replacement confusion

Adam Vande More amvandemore at gmail.com
Thu Aug 11 17:24:40 UTC 2011


On Thu, Aug 11, 2011 at 11:51 AM, Jeremy Chadwick
<freebsd at jdc.parodius.com>wrote:

> The problem is something I have run into myself many times.  It's a
> syntax-specific "quirk" with the zpool command, and ONLY applies when
> working with mirrors.  Furthermore, the "gotcha" may be gone with ZFSv28
> (which you aren't running); I'm not sure.
>
> The "quirk" is that you have to specify the name of an existing
> (working) mirror device *before* the new device you're attempting to
> integrate.  E.g. "zpool {command} pool {existingdev} {newdev}", rather
> than "zpool {command} pool {newdev}".  Failure to provide the name of
> the device of the existing mirror member results in the pool becoming
> a stripe, which you have no way to recover from without recreating the
> entire pool.
>
> I would show you an example but all my systems run ZFSv28 and I can't
> seem to find any online documentation which helps back up my statement.
> I hope someone else here can phrase what I'm trying to say in a more
> eloquent manner and provide documentation/references confirming it.
>

I think you mean this but I'm not sure I'd agree it's a quirk.  If there is
an understanding of zpools, mirrors, and vdev's it seems like a logical
syntax.  However, the unforgiving nature of vdev's does put some fear in me
whenever I make an change.

http://www.solarisinternals.com/wiki/index.php/ZFS_Troubleshooting_Guide#Disk_Replacement_Example

-- 
Adam Vande More


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