From: Dave Chinner <david@fromorbit.com>
To: Peter Niemayer <niemayer@isg.de>
Cc: linux-xfs@oss.sgi.com
Subject: Re: observed significant performance improvement using "delaylog" in a real-world application
Date: Thu, 12 Aug 2010 09:44:20 +1000 [thread overview]
Message-ID: <20100811234420.GA10429@dastard> (raw)
In-Reply-To: <i3ul1b$d3b$1@dough.gmane.org>
On Wed, Aug 11, 2010 at 07:01:31PM +0200, Peter Niemayer wrote:
> On 08/11/2010 02:28 PM, Michael Monnerie wrote:
> >Thank you. Are those files located within one dir or do you use a hash
> >structure like squid cache does?
>
> There's only a shallow hierarchy (for functional, not for distribution
> reasons), so the relevant directories have thousands of files in them.
>
> I think after the "ext2"-age no serious file system ever had
> a real problem dealing with lots of files in one directory -
> or do you have contradicting information?
Define "lots of files". :)
>From my numbers, ext3/4 still fall way behind XFS and btrfs when it
comes to handling directories with tens of thousands of entries or
larger. Especially on cold-cache random lookups.
XFS also has quite sophisticated internal directory readahead, so
under the cold cache directory performance of XFS is far better than
ext3/4 can acheive, even for relatively small directories. IIRC this
difference in directory lookup performance was one of the prime
reasons kernel.org switched from ext3 to XFS a couple of years
back...
Cheers,
Dave.
--
Dave Chinner
david@fromorbit.com
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prev parent reply other threads:[~2010-08-11 23:44 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2010-08-10 16:01 observed significant performance improvement using "delaylog" in a real-world application Peter Niemayer
2010-08-11 0:08 ` Dave Chinner
2010-08-11 18:08 ` Peter Niemayer
2010-08-11 8:03 ` Michael Monnerie
2010-08-11 9:45 ` Peter Niemayer
2010-08-11 12:28 ` Michael Monnerie
2010-08-11 17:01 ` Peter Niemayer
2010-08-11 22:31 ` Michael Monnerie
2010-08-11 23:44 ` Dave Chinner [this message]
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