From: Hugo Mills <hugo@carfax.org.uk>
To: Martin Steigerwald <Martin@lichtvoll.de>
Cc: linux-btrfs@vger.kernel.org,
"Ronnie Collinson" <notthinking@gmail.com>,
"Michael Kjörling" <michael@kjorling.se>
Subject: Re: How does btrfs behave on checksum mismatch?
Date: Sun, 28 Oct 2012 13:39:43 +0000 [thread overview]
Message-ID: <20121028133943.GD5042@carfax.org.uk> (raw)
In-Reply-To: <201210281436.24540.Martin@lichtvoll.de>
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On Sun, Oct 28, 2012 at 02:36:24PM +0100, Martin Steigerwald wrote:
> Am Sonntag, 28. Oktober 2012 schrieb Hugo Mills:
> > On Sun, Oct 28, 2012 at 02:23:51PM +0100, Martin Steigerwald wrote:
> > > Am Sonntag, 28. Oktober 2012 schrieb Ronnie Collinson:
> > > > In a raid1 situation, it will also rewrite the effected data, on
> > > > the drive that failed the checksum
> > >
> > > Will it do so without an explicit scrub?
> >
> > If a failed checksum is detected, yes.
> >
> > If there's a bad block, and the FS happens to read the good copy
> > first, it won't fix it, because it hasn't tried reading the bad copy
> > yet.
>
> Ah, okay. I think I read some while ago in a case of bad checksum detected
> it won´t repair automatically. Has this been changed?
It was changed some time ago -- the kernel release after scrub went
in, IIRC.
> Anyway, a regular scrub still makes sense, as BTRFS only reads files that
> applications demand and BTRFS may read from a good copy as you pointed
> out.
Indeed. I have a cron job in /etc/cron.monthy for my main FS to do
just that.
Hugo.
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prev parent reply other threads:[~2012-10-28 13:39 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-10-27 21:56 How does btrfs behave on checksum mismatch? Michael Kjörling
2012-10-27 22:02 ` Hugo Mills
2012-10-27 22:09 ` Michael Kjörling
2012-10-28 12:23 ` Ronnie Collinson
2012-10-28 13:23 ` Martin Steigerwald
2012-10-28 13:26 ` Hugo Mills
2012-10-28 13:36 ` Martin Steigerwald
2012-10-28 13:39 ` Hugo Mills [this message]
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