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Re: fsfs and Linux filesystems

From: Ph. Marek <philipp.marek_at_bmlv.gv.at>
Date: 2005-09-16 07:35:22 CEST

On Sunday 28 August 2005 15:04, Christopher Ness wrote:
> If I understand fsfs correctly it uses lots of small-medium sized files.
> Each revision is in it's own file in ./db/revs/[0-9]+
>
> Therefore this article about FS suggests that ReiserFS should be the
> best for storing many small files.
> http://www.linux-mag.com/2002-10/jfs_01.html
>
> To quote the article, about 1/2 way down the page:
> "ReiserFS is about eight to fifteen times faster than Ext2 at handling
> files smaller than 1K."
>
> That being said, even a simple revision was 1.3K in a FSFS type file
> system (ext3) so perhaps this is not applicable. I would expect
> revisions to be anywhere between 2K to 100K on average for text based
> revisions. Binaries and all bets are off.
>
> All that is needed is some actual data tests on the different FS'. ;)
>
> ReiserFS publishes some of their own benchmarks:
> http://www.namesys.com/benchmarks.html#mongo.2.6.11
Just another datapoint for the server (svnserve) side of view:

Using fsfs and committing ~150000 files/directories at once with properties
for _each_ file and directory resulted in ~300000 files _in one directory_ -
which got a bit slow, especially as I had no directory index activated on
this filesystem. That's a point where fsfs could do much better - instead of
dropping all files in a single directory. (Yes, I know, that opens the can of
worms - but I won't participate in discussing "should it/should it not". _I_
don't like it.)

A hint for people using ext3:

Check your filesystem with "tune2fs -l /dev/<block_device>". If you don't see
dir_index in the features line, I'd suggest enabling it with "tune2fs -O
dir_index /dev/<block_device>".

I went to bdb, which has a nearly fixed number of files - and that's *much*
faster. (Although I'd prefer fsfs)

If I have the time I'll try to test on reiserfs, too.

Regards,

Phil

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Received on Fri Sep 16 07:37:49 2005

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