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Re: Mount options for Optimizing ext2/ext3 performance with Maildir's



On Tue, 19 Oct 2004 02:15, Ian Forbes <iforbes@zsd.co.za> wrote:
> Is ext3 faster or slower than ext2?

If you use an external journal on a fast device then ext3 should be much 
faster.

> What mount options give the best performance, "noatime" "data=journal" ?

noatime is (IMHO) mandatory for a Maildir based mail server.  It seriously 
decreases the load while not removing any feature that you desire.  Make sure 
that you set noatime on the root file system as well as the mail store, 
otherwise you get a lot of writes to the root FS every time a POP server is 
started.

> Currently I have everything in one big root partition. If I mount it with
> "noatime" will a hole bunch of things stop working, like the automatic
> reloading of files in /etc/cron.d/ ?

Nothing will stop working.  cron uses the mtime.

finger won't tell you the inactivity time of sessions from users who login at 
the console if /dev is on a file system with noatime, this is no real loss 
(and udev can fix this).

> With the options data=journal / data=ordered / data=writeback which will
> give me the best performance and which has the biggest chance of data loss
> in a crash situation.  I think I can live with mail that is being delivered
> at the moment of a crash getting corrupted, provided that the server is
> never rendered un-bootable and that no other files are effected.

I think that you will have to do your own benchmarks of this.

> The system is running with a 2.4.18. Is there anything to be gained from
> upgrading to a later 2.4 or a 2.6 kernel.

If you use a 2.6 kernel then you get directory hashing which can significantly 
improve performance when you have large numbers of directory entries.  This 
will help if you have a large number of user mail store directories in one 
directory, if you have a large number of email files in one Maildir 
directory, or if you have a large number of temporary files in one spool 
directory under /var/spool.  Generally you can expect some significant 
performance increases from 2.6.x kernels.

-- 
http://www.coker.com.au/selinux/   My NSA Security Enhanced Linux packages
http://www.coker.com.au/bonnie++/  Bonnie++ hard drive benchmark
http://www.coker.com.au/postal/    Postal SMTP/POP benchmark
http://www.coker.com.au/~russell/  My home page



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