From: Stan Hoeppner <stan@hardwarefreak.com>
To: David Brown <david.brown@hesbynett.no>
Cc: Roy Sigurd Karlsbakk <roy@karlsbakk.net>,
Linux Raid <linux-raid@vger.kernel.org>,
Bernd Schubert <bernd.schubert@fastmail.fm>
Subject: Re: Checksumming RAID?
Date: Tue, 27 Nov 2012 14:49:04 -0600 [thread overview]
Message-ID: <50B52740.5000201@hardwarefreak.com> (raw)
In-Reply-To: <50B4B40B.3000807@hesbynett.no>
On 11/27/2012 6:37 AM, David Brown wrote:
> To do checksumming (and in particular, recovery), requires higher level
> knowledge of the data. The filesystem can track when it writes a file,
> and update metadata (including, if desired, a data checksum) once it
> knows the file is correctly stored. But I don't think it can sensibly
> be done at the block device level - the recovery procedure doesn't know
> what is old data, what is new data, or which bit is important to the
> filesystem.
>
> So I think it can make sense to use a filesystem like ZFS or BTRFS that
> can do checksumming - that is a reasonable level to add the checksum.
You'll see CRC in XFS in the future as well. Some of the foundation is
already laid to allow it, but IIRC it requires an on disk format change
for full implementation. On disk format changes are a big deal and are
taken with great care. IIRC XFS has only seen one or two in 18 years.
--
Stan
next prev parent reply other threads:[~2012-11-27 20:49 UTC|newest]
Thread overview: 32+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-11-26 13:27 Checksumming RAID? Roy Sigurd Karlsbakk
2012-11-27 9:45 ` David Brown
2012-11-27 10:17 ` Bernd Schubert
2012-11-27 11:20 ` David Brown
2012-11-27 11:39 ` Roy Sigurd Karlsbakk
2012-11-27 12:37 ` David Brown
2012-11-27 13:09 ` Roy Sigurd Karlsbakk
2012-11-27 13:20 ` David Brown
2012-11-27 13:56 ` Roy Sigurd Karlsbakk
2012-11-27 14:34 ` David Brown
2012-11-27 20:49 ` Stan Hoeppner [this message]
2012-11-28 10:58 ` Roy Sigurd Karlsbakk
2012-11-27 12:31 ` Bernd Schubert
2012-11-27 13:05 ` David Brown
2012-11-27 18:53 ` Chris Murphy
2012-11-27 19:27 ` Roy Sigurd Karlsbakk
2012-11-27 19:50 ` Chris Murphy
2012-11-28 10:56 ` Roy Sigurd Karlsbakk
2012-11-28 10:59 ` Roy Sigurd Karlsbakk
2012-11-28 13:25 ` Drew
2012-11-28 17:51 ` Roy Sigurd Karlsbakk
2012-11-28 19:16 ` Chris Murphy
2012-11-28 19:08 ` Chris Murphy
2012-11-28 19:18 ` Roy Sigurd Karlsbakk
2012-11-28 20:02 ` Chris Murphy
2012-11-27 13:54 ` Joe Landman
2012-11-27 18:48 ` Chris Murphy
2012-11-27 19:36 ` Chris Murphy
2012-12-03 12:24 ` Pasi Kärkkäinen
2012-12-03 14:09 ` Checksumming RAID? / SCSI SAS T10 PI and DIF/DIX / T13 SATA EPP Pasi Kärkkäinen
2012-12-05 19:05 ` Martin K. Petersen
2012-12-06 11:10 ` John Robinson
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