From: Ric Wheeler <rwheeler@redhat.com>
To: Julien FERRERO <jferrero06@gmail.com>
Cc: xfs@oss.sgi.com
Subject: Re: XFS filesystem corruption
Date: Thu, 07 Mar 2013 08:40:36 -0500 [thread overview]
Message-ID: <513898D4.6030502@redhat.com> (raw)
In-Reply-To: <CAPcwv6wK7m5UbJZass5690N5UpXEMV+HVzJa5mn9KWtT9UPQ9w@mail.gmail.com>
On 03/07/2013 08:15 AM, Julien FERRERO wrote:
>> We actually test brutal "Power off" for xfs, ext4 and other file systems. If
>> your storage is configured properly and you have barriers enabled, they all
>> pass without corruption.
>>
>> What hardware raid cards can do is to hide a volatile write cache. Either on
>> the raid HBA itself or, even worse, on the backend disks behind the card.
>> S-ata disks tend to default to write cache enabled and need to be checked
>> especially careful (sas drives tend to be write cache disabled by default).
> Write cache is supposed to be disabled on the H/W RAID (according to
> hdparm) and barrier are correctly enabled since xfs does not report
> any warning at mount.
hdparm shows you the devices that the card shows, not the state of the write
cache on the drives behind them.
You need special vendor tools to do....
The LSI controllers for example have megaraid tools.
Until your IO stack is properly configured, you really don't need to worry about
the file system options :)
ric
>
> The odd thing is we never see this with kernel 2.6.18 where barriers
> weren't yet available. An other difference is the "unwritten extend"
> that was used to set to 0 by default. Now we cannot change this
> setting according to an old thread I've found: "unwritten extents on
> linux are generally a bad idea, this option should not be used.".
> Unfortunately, the engineer that chose this setting is no longer
> working with us...
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next prev parent reply other threads:[~2013-03-07 13:40 UTC|newest]
Thread overview: 31+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-03-06 15:08 XFS filesystem corruption Julien FERRERO
2013-03-06 15:15 ` Emmanuel Florac
2013-03-06 16:16 ` Julien FERRERO
2013-03-06 16:47 ` Ric Wheeler
2013-03-06 22:21 ` Emmanuel Florac
2013-03-06 23:12 ` Ric Wheeler
2013-03-07 13:15 ` Julien FERRERO
2013-03-07 13:40 ` Ric Wheeler [this message]
2013-03-07 23:22 ` Dave Chinner
2013-03-08 10:16 ` Julien FERRERO
2013-03-12 9:57 ` Martin Steigerwald
2013-03-08 8:39 ` Stan Hoeppner
2013-03-08 10:17 ` Julien FERRERO
2013-03-08 12:20 ` Ric Wheeler
2013-03-08 18:59 ` Stan Hoeppner
2013-03-09 9:11 ` Dave Chinner
2013-03-09 18:51 ` Stan Hoeppner
2013-03-10 22:45 ` Dave Chinner
2013-03-10 23:54 ` Stan Hoeppner
2013-03-11 0:50 ` Dave Chinner
2013-03-11 9:29 ` Stan Hoeppner
2013-03-11 22:45 ` Dave Chinner
2013-03-11 9:25 ` Julien FERRERO
2013-03-12 10:54 ` Emmanuel Florac
2013-03-12 10:42 ` Martin Steigerwald
2013-03-12 22:16 ` Stan Hoeppner
2013-03-07 3:56 ` Stan Hoeppner
2013-03-07 13:04 ` Julien FERRERO
2013-03-07 13:32 ` Stan Hoeppner
2013-03-10 2:50 ` Eric Sandeen
2013-03-10 22:11 ` Dave Chinner
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