Troubleshooting a gmirror disk marked broken

Adam Vande More amvandemore at
Thu Jun 27 16:58:07 UTC 2013

On Thu, Jun 27, 2013 at 10:16 AM, Charles Swiger <cswiger at> wrote:

> If you haven't rebuilt the mirror already, running a full disk read scan
> against both drives (ie, via "dd if=/dev/ad4 of=/dev/null bs=1m" or
> similar)
> might be prudent.  That will help identify/migrate any sectors which are
> failing but still recoverable via ECC to the spare sectors.

I was going to say something like that too but AFAIK sectors aren't
remapped on failed reads, has to be written to(dd if=/dev/zero of=/dev/ad4
bs=1m).  If it were me, I make sure I had fully tested complete backups
before I broke the mirror and did that.

Adam Vande More

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