Skip site navigation (1)Skip section navigation (2)
Date:      Thu, 27 Jun 2013 10:06:45 -0700
From:      Charles Swiger <cswiger@mac.com>
To:        Adam Vande More <amvandemore@gmail.com>
Cc:        =?utf-8?Q?Nikola_Pavlovi=C4=87?= <nzp@riseup.net>, FreeBSD Questions <freebsd-questions@freebsd.org>
Subject:   Re: Troubleshooting a gmirror disk marked broken
Message-ID:  <0469490B-A577-40DA-9A04-910150330E16@mac.com>
In-Reply-To: <CA+tpaK0rT83sMcaQTsg3m31Gr2RrnZBTbDgr-sZyWAS_6fzS5w@mail.gmail.com>
References:  <20130627023837.GA7685@sputnjik.localdomain> <36C962B9-ABC4-45E3-AC94-46D6CEE960E1@mac.com> <CA+tpaK0rT83sMcaQTsg3m31Gr2RrnZBTbDgr-sZyWAS_6fzS5w@mail.gmail.com>

Next in thread | Previous in thread | Raw E-Mail | Index | Archive | Help
Hi--

On Jun 27, 2013, at 9:58 AM, Adam Vande More <amvandemore@gmail.com> =
wrote:
> On Thu, Jun 27, 2013 at 10:16 AM, Charles Swiger <cswiger@mac.com> =
wrote:
>> If you haven't rebuilt the mirror already, running a full disk read =
scan
>> against both drives (ie, via "dd if=3D/dev/ad4 of=3D/dev/null bs=3D1m" =
or similar)
>> might be prudent.  That will help identify/migrate any sectors which =
are
>> failing but still recoverable via ECC to the spare sectors.
>=20
> 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=3D/dev/zero =
of=3D/dev/ad4 bs=3D1m).  If it were me, I make sure I had fully tested =
complete backups before I broke the mirror and did that.


If the drive reads a sector with ECC-correctable errors, it's supposed =
to try to re-write that sector in order to fix up the ECC data.  If that =
write fails, it remaps.

Of course, your suggestion of blanking the entire drive and restoring =
from the mirror or a backup would be best, or perhaps "better short of =
replacing the drive".

Regards,
--=20
-Chuck





Want to link to this message? Use this URL: <http://docs.FreeBSD.org/cgi/mid.cgi?0469490B-A577-40DA-9A04-910150330E16>