From: Robert White <rwhite@pobox.com>
To: Chris Murphy <lists@colorremedies.com>,
Btrfs BTRFS <linux-btrfs@vger.kernel.org>
Subject: Re: RAID1 fails to recover chunk tree
Date: Sat, 01 Nov 2014 21:26:06 -0700 [thread overview]
Message-ID: <5455B25E.2070703@pobox.com> (raw)
In-Reply-To: <FC480E52-012E-41E7-902E-2EE3ECFFB90B@colorremedies.com>
On 10/30/2014 07:09 PM, Chris Murphy wrote:
> Is hard to say. If a balance hasn't recently been done, the original device may have a good amount of free space in allocated chunks. I'm pretty sure Btrfs will write first to already allocated chunks with free space before allocating new chunks? So a bunch of stuff could actually still be on the original device - it just needs -o degraded,ro to get access to it. And if the current version of the file isn't retrievable because all or part of it's on the other drive, it'll just cause an error to occur. I think rsync and the like can be set to not fail on such errors, so anything that can be retrieved, is.
Way back when he said that he "set the metadata to raid1" (or the
equivalent). That is, he didn't just rely on the default duplicaiton
onto the second drive. The only way I know to explicitly do that is with
the mfilter option to balance. So I'm pretty sure that, statistically,
about half his data is gone.
next prev parent reply other threads:[~2014-11-02 4:26 UTC|newest]
Thread overview: 23+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-10-28 20:32 RAID1 fails to recover chunk tree Zack Coffey
2014-10-29 3:55 ` Anand Jain
2014-10-29 19:32 ` Zack Coffey
2014-10-30 3:33 ` Anand Jain
2014-10-29 22:26 ` Robert White
2014-10-29 23:07 ` Robert White
2014-10-30 13:30 ` Zack Coffey
2014-10-30 15:23 ` Zygo Blaxell
2014-10-30 18:04 ` Chris Murphy
2014-10-31 1:27 ` Duncan
2014-10-31 2:09 ` Chris Murphy
2014-11-02 4:26 ` Robert White [this message]
2014-11-02 8:48 ` Roman Mamedov
2014-11-02 11:08 ` Robert White
2014-11-03 6:52 ` Duncan
2014-11-03 8:00 ` Duncan
2014-10-31 8:35 ` Robert White
2014-10-31 12:15 ` Zack Coffey
2014-11-02 4:19 ` Robert White
-- strict thread matches above, loose matches on Subject: below --
2014-10-28 20:18 Zack Coffey
2014-10-27 19:01 Zack Coffey
2014-10-15 21:09 Zack Coffey
2014-10-15 15:42 Zack Coffey
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