From: Gert Menke <gert@menke.ac>
To: Hugo Mills <hugo@carfax.org.uk>, linux-btrfs@vger.kernel.org
Subject: Re: BTRFS as image store for KVM?
Date: Thu, 17 Sep 2015 23:49:10 +0200 [thread overview]
Message-ID: <55FB3556.1070004@menke.ac> (raw)
In-Reply-To: <20150917194314.GA29926@carfax.org.uk>
On 17.09.2015 at 21:43, Hugo Mills wrote:
> On Thu, Sep 17, 2015 at 07:56:08PM +0200, Gert Menke wrote:
>> BTRFS looks really nice feature-wise, but is not (yet) optimized for
>> my use-case I guess. Disabling COW would certainly help, but I don't
>> want to lose the data checksums. Is nodatacowbutkeepdatachecksums a
>> feature that might turn up in the future?
> [snip]
>
> No. If you try doing that particular combination of features, you
> end up with a filesystem that can be inconsistent: there's a race
> condition between updating the data in a file and updating the csum
> record for it, and the race can't be fixed.
I'm no filesystem expert, but isn't that what an intent log is for?
(Does btrfs have an intent log?)
And, is this also true for mirrored or raid5 disks?
I'm thinking something like "if the data does not match the checksum,
just restore both from mirror/parity" should be possible, right?
Gert
next prev parent reply other threads:[~2015-09-17 21:49 UTC|newest]
Thread overview: 45+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-09-15 21:34 BTRFS as image store for KVM? Gert Menke
2015-09-16 3:00 ` Chris Murphy
2015-09-16 3:57 ` Duncan
2015-09-16 11:35 ` Brendan Heading
2015-09-16 12:25 ` Austin S Hemmelgarn
2015-09-16 12:41 ` Paul Jones
2015-09-17 17:56 ` Gert Menke
2015-09-17 18:35 ` Chris Murphy
2015-09-17 21:32 ` Gert Menke
2015-09-18 2:00 ` Duncan
2015-09-18 8:32 ` Gert Menke
2015-09-23 7:28 ` Russell Coker
2015-09-18 14:13 ` Austin S Hemmelgarn
2015-09-23 7:24 ` Russell Coker
2015-09-17 18:46 ` Mike Fleetwood
2015-09-17 19:43 ` Hugo Mills
2015-09-17 21:49 ` Gert Menke [this message]
2015-09-18 2:22 ` Duncan
2015-09-18 8:59 ` Gert Menke
2015-09-17 22:41 ` Sean Greenslade
2015-09-18 7:34 ` Gert Menke
2015-09-17 4:19 ` Paul Harvey
2015-09-20 1:26 ` Jim Salter
2015-09-25 12:48 ` Rich Freeman
2015-09-25 12:56 ` Jim Salter
2015-09-25 13:04 ` Austin S Hemmelgarn
[not found] ` <5605483A.7040103@jrs-s.net>
2015-09-25 13:46 ` Austin S Hemmelgarn
2015-09-25 13:52 ` Jim Salter
2015-09-25 14:02 ` Timofey Titovets
2015-09-25 14:20 ` Austin S Hemmelgarn
2015-09-29 14:12 ` Gert Menke
2015-10-02 4:21 ` Russell Coker
2015-10-02 12:07 ` Austin S Hemmelgarn
2015-10-03 8:32 ` Russell Coker
2015-10-04 2:09 ` Duncan
2015-10-04 12:03 ` Lionel Bouton
2015-10-04 12:21 ` Rich Freeman
2015-10-05 8:19 ` Duncan
2015-10-05 8:43 ` Erkki Seppala
2015-10-05 8:51 ` Roman Mamedov
2015-10-05 11:16 ` Lionel Bouton
2015-10-05 11:40 ` Rich Freeman
2015-10-05 11:54 ` Austin S Hemmelgarn
[not found] ` <RPG31r00t34oj7R01PG5Us>
2015-10-05 14:04 ` Duncan
2015-10-05 15:59 ` Austin S Hemmelgarn
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