From: Florian Weimer <fweimer@bfk.de>
To: Stewart Smith <stewart@flamingspork.com>
Cc: Christoph Hellwig <hch@infradead.org>, xfs@oss.sgi.com
Subject: Re: XFS on 2.6.26: reading the first 4K of a large file takes ages
Date: Fri, 21 May 2010 06:43:15 +0000 [thread overview]
Message-ID: <828w7d69h8.fsf@mid.bfk.de> (raw)
In-Reply-To: <87zkztojwh.fsf@willster.local.flamingspork.com> (Stewart Smith's message of "Fri\, 21 May 2010 16\:20\:46 +1000")
* Stewart Smith:
> On Thu, 20 May 2010 12:11:00 +0000, Florian Weimer <fweimer@bfk.de> wrote:
>> Thanks for confirming my hunch. I don't think it's worth fixing this
>> in XFS. The database should call posix_fallocate() before flushing
>> its internal cache to the file in essentially random order, but it's
>> difficult to get upstream to implement this (the source code is a bit
>> hard to follow, unfortunately).
>
> Which database?
Oracle Berkeley DB.
> You could always mount with allocsize
This happens with "allocsize=4194304".
> or use other tools to do the preallocation before things got too
> bad.
Is there a way to transparently preallocate a few GB after the current
end of the file? That would be helpful because Berkeley DB wouldn't
have to know about it.
It's a legacy system, otherwise I would invest more effort into
putting some sort of preallocation somewhere deep into Berkeley DB.
--
Florian Weimer <fweimer@bfk.de>
BFK edv-consulting GmbH http://www.bfk.de/
Kriegsstraße 100 tel: +49-721-96201-1
D-76133 Karlsruhe fax: +49-721-96201-99
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next prev parent reply other threads:[~2010-05-21 6:41 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2010-05-19 11:33 XFS on 2.6.26: reading the first 4K of a large file takes ages Florian Weimer
2010-05-19 11:48 ` Christoph Hellwig
2010-05-19 23:27 ` Dave Chinner
2010-05-20 12:11 ` Florian Weimer
2010-05-21 6:20 ` Stewart Smith
2010-05-21 6:43 ` Florian Weimer [this message]
2010-05-21 8:26 ` Dave Chinner
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