XFS vs Elevators (was Re: [PATCH RFC] nilfs2: continuous snapshotting file system)
----- Original Message ----
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From: Dave Chinner <[email protected]>
To: Szabolcs Szakacsits <[email protected]>; Andrew Morton <[email protected]>; [email protected]; [email protected]; [email protected]
Sent: Thursday, August 21, 2008 10:25:32 AM
Subject: Re: XFS vs Elevators (was Re: [PATCH RFC] nilfs2: continuous snapshotting file system)Quoted 5 lines · Dave Chinner
Quoted 4 lines · Dave Chinner
Quoted 3 lines · Szabolcs Szakacsits
On Thu, 21 Aug 2008, Dave Chinner wrote:
Everything is default.Quoted 7 lines
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% rpm -qf =mkfs.xfs
xfsprogs-2.9.8-7.1which, according to ftp://oss.sgi.com/projects/xfs/cmd_tars, is the latest stable mkfs.xfs. Its output is
meta-data=/dev/sda8 isize=256 agcount=4, agsize=1221440
blks
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= sectsz=512 attr=2 data = bsize=4096 blocks=4885760, imaxpct=25 = sunit=0 swidth=0 blks naming =version 2 bsize=4096 log =internal log bsize=4096 blocks=2560, version=2 = sectsz=512 sunit=0 blks, lazy-count=0 realtime =none extsz=4096 blocks=0, rtextents=0Ok, I thought it might be the tiny log, but it didn't improve anything here when increased the log size, or the log buffer size.
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One thing I just found out - my old *laptop* is 4-5x faster than the 10krpm scsi disk behind an old cciss raid controller. I'm wondering if the long delays in dispatch is caused by an interaction with CTQ but I can't change it on the cciss raid controllers. Are you using ctq/ncq on your machine? If so, can you reduce the depth to something less than 4 and see what difference that makes?
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Just to point out - this is not a new problem - I can reproduce it on 2.6.24 as well as 2.6.26. Likewise, my laptop shows XFS being faster than ext3 on both 2.6.24 and 2.6.26. So the difference is something related to the disk subsystem on the server....
Hi Dave,
just curious - which CCISS controller and and what kind of disk configuration are you using.
Cheers
Martin
Quoted 1 line · Martin Knoblauch
just curious - which CCISS controller and and what kind of disk configuration are you using.
Smart Array 5300, using a single 36GB 10krpm U3SCSI disk.
Looks like most of the problems were caused by the firmware, and are not driver related. An upgrade to a newer (2002!) firmware appears to have fixed the worst of the problems.
Cheers,
Dave.
Signature · 2 lines
Dave Chinner [email protected]