From: Chris Murphy <lists@colorremedies.com>
To: kreijack@inwind.it
Cc: Zygo Blaxell <ce3g8jdj@umail.furryterror.org>,
Chris Murphy <lists@colorremedies.com>,
Roman Mamedov <rm@romanrm.net>,
Btrfs BTRFS <linux-btrfs@vger.kernel.org>
Subject: Re: Adventures in btrfs raid5 disk recovery
Date: Thu, 23 Jun 2016 18:26:22 -0600 [thread overview]
Message-ID: <CAJCQCtRXqSCFZTca+Vwraa0vS-MzLQKEkr=s41Vypc-O0ZDdxQ@mail.gmail.com> (raw)
In-Reply-To: <5790aea9-0976-1742-7d1b-79dbe44008c3@inwind.it>
On Thu, Jun 23, 2016 at 1:32 PM, Goffredo Baroncelli <kreijack@inwind.it> wrote:
>
> The raid5 write hole is avoided in BTRFS (and in ZFS) thanks to the checksum.
Yeah I'm kinda confused on this point.
https://btrfs.wiki.kernel.org/index.php/RAID56
It says there is a write hole for Btrfs. But defines it in terms of
parity possibly being stale after a crash. I think the term comes not
from merely parity being wrong but parity being wrong *and* then being
used to wrongly reconstruct data because it's blindly trusted.
I don't read code well enough, but I'd be surprised if Btrfs
reconstructs from parity and doesn't then check the resulting
reconstructed data to its EXTENT_CSUM.
--
Chris Murphy
next prev parent reply other threads:[~2016-06-24 0:26 UTC|newest]
Thread overview: 68+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-06-20 3:44 Adventures in btrfs raid5 disk recovery Zygo Blaxell
2016-06-20 18:13 ` Roman Mamedov
2016-06-20 19:11 ` Zygo Blaxell
2016-06-20 19:30 ` Chris Murphy
2016-06-20 20:40 ` Zygo Blaxell
2016-06-20 21:27 ` Chris Murphy
2016-06-21 1:55 ` Zygo Blaxell
2016-06-21 3:53 ` Zygo Blaxell
2016-06-22 17:14 ` Chris Murphy
2016-06-22 20:35 ` Zygo Blaxell
2016-06-23 19:32 ` Goffredo Baroncelli
2016-06-24 0:26 ` Chris Murphy [this message]
2016-06-24 1:47 ` Zygo Blaxell
2016-06-24 4:02 ` Andrei Borzenkov
2016-06-24 8:50 ` Hugo Mills
2016-06-24 9:52 ` Andrei Borzenkov
2016-06-24 10:16 ` Hugo Mills
2016-06-24 10:19 ` Andrei Borzenkov
2016-06-24 10:59 ` Hugo Mills
2016-06-24 11:36 ` Austin S. Hemmelgarn
2016-06-24 17:40 ` Chris Murphy
2016-06-24 18:06 ` Zygo Blaxell
2016-06-24 17:06 ` Chris Murphy
2016-06-24 17:21 ` Andrei Borzenkov
2016-06-24 17:52 ` Chris Murphy
2016-06-24 18:19 ` Austin S. Hemmelgarn
2016-06-25 16:44 ` Chris Murphy
2016-06-25 21:52 ` Chris Murphy
2016-06-26 7:54 ` Andrei Borzenkov
2016-06-26 15:03 ` Duncan
2016-06-26 19:30 ` Chris Murphy
2016-06-26 19:52 ` Zygo Blaxell
2016-06-27 11:21 ` Austin S. Hemmelgarn
2016-06-27 16:17 ` Chris Murphy
2016-06-27 20:54 ` Chris Murphy
2016-06-27 21:02 ` Henk Slager
2016-06-27 21:57 ` Zygo Blaxell
2016-06-27 22:30 ` Chris Murphy
2016-06-28 1:52 ` Zygo Blaxell
2016-06-28 2:39 ` Chris Murphy
2016-06-28 3:17 ` Zygo Blaxell
2016-06-28 11:23 ` Austin S. Hemmelgarn
2016-06-28 12:05 ` Austin S. Hemmelgarn
2016-06-28 12:14 ` Steven Haigh
2016-06-28 12:25 ` Austin S. Hemmelgarn
2016-06-28 16:40 ` Steven Haigh
2016-06-28 18:01 ` Chris Murphy
2016-06-28 18:17 ` Steven Haigh
2016-07-05 23:05 ` Chris Murphy
2016-07-06 11:51 ` Austin S. Hemmelgarn
2016-07-06 16:43 ` Chris Murphy
2016-07-06 17:18 ` Austin S. Hemmelgarn
2016-07-06 18:45 ` Chris Murphy
2016-07-06 19:15 ` Austin S. Hemmelgarn
2016-07-06 21:01 ` Chris Murphy
2016-06-24 16:52 ` Chris Murphy
2016-06-24 16:56 ` Hugo Mills
2016-06-24 16:39 ` Zygo Blaxell
2016-06-24 1:36 ` Zygo Blaxell
2016-06-23 23:37 ` Chris Murphy
2016-06-24 2:07 ` Zygo Blaxell
2016-06-24 5:20 ` Chris Murphy
2016-06-24 10:16 ` Andrei Borzenkov
2016-06-24 17:33 ` Chris Murphy
2016-06-24 11:24 ` Austin S. Hemmelgarn
2016-06-24 16:32 ` Zygo Blaxell
2016-06-24 2:17 ` Zygo Blaxell
2016-06-22 4:06 ` Adventures in btrfs raid5 disk recovery - update Zygo Blaxell
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