From: Michael Monnerie <michael.monnerie@is.it-management.at>
To: xfs@oss.sgi.com
Subject: xfs preallocation timeout
Date: Wed, 11 Feb 2009 15:22:11 +0100 [thread overview]
Message-ID: <200902111522.11987@zmi.at> (raw)
Does /proc/sys/vm/dirty_expire_centisecs influence the maximum time XFS
takes before the "in-memory but not on disk" preallocation actually
starts writing to disk? If not, which parameter does influence how long
files are grouped together in memory before writing them really to disk?
The longer the better for performance, but more risk for data loss of
course.
I ask this because I want to know when copying files over the net to an
XFS drive, how I can prevent fragmentation to occur. Example: If a
packet of 1024 Bytes arrives every 1/100th second, it needs 0.64s to get
64KB of data, 1.28s to get 128KB. If the prealloc timeout is one second,
it's effectively not used in this case. So if you got a server where you
know files arrive at a certain speed, fine tuning this prealloc timeout
could help prevent fragmentation.
mfg zmi
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next reply other threads:[~2009-02-11 14:23 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2009-02-11 14:22 Michael Monnerie [this message]
2009-02-12 22:08 ` xfs preallocation timeout Dave Chinner
2009-02-13 9:35 ` Michael Monnerie
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