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Re: [Linux-cluster] GFS performance of imap service (Maildir)



Hi,

could you strace your imapd process ? Please add the -T option to print the 
time the process spent in the system calls.

-Mark

On Friday 21 November 2008 17:46:00 Achievement Chan wrote:
> Hello,
> I will change my production system to ext3 for solving the performance
> problem. Actually, I have tried GFS2 in testing server and found
> performance can be improved to a acceptable level (response within 2
> seconds)
>
> However, it still not stable for production system.... and I can't
> wait until RHEL 5.3 release...
>
> 2008/11/13 Kadlecsik Jozsef <kadlec sunserv kfki hu>:
> > Hello,
> >
> > On Wed, 12 Nov 2008, Achievement Chan wrote:
> >> For handling a mailbox with 10000 email, it takes 6-8 seconds for
> >> waiting response from first "SELECT" command.
> >> The response time is also unstable too, sometimes it takes 10-20
> >> seconds for the same mailbox.
> >>
> >> Based some online material, i've tried to tune the gfs. But there are
> >> seems no improvement.
> >> e.g.
> >> gfs_tool setflag inherit_jdata /home/domains
> >> gfs_tool  settune /home/domains recoverd_secs 60
> >> gfs_tool settune /home/domains glock_purge 50
> >> gfs_tool settune /home/domains demote_secs 100
> >> gfs_tool settune /home/domains scand_secs 3
> >> gfs_tool settune /home/domains max_readahead 262144
> >> gfs_tool settune /home/domains statfs_fast 1
> >>
> >> Has anyone tried to provide imap service in GFS?
> >
> > We have had exactly the same problems with maildir over GFS. There was no
> > tuning whatsoever which helped: the fighting for the locks for every
> > file in the maildir costs so much that you cannot expect better
> > performance.
> >
> > The best is to avoid maildir and use simple mailbox format instead. We
> > went (back) to mailbox and since then our users have not complained about
> > performance.
> >
> > Best regards,
> > Jozsef
> > --
> > E-mail : kadlec mail kfki hu, kadlec blackhole kfki hu
> > PGP key: http://www.kfki.hu/~kadlec/pgp_public_key.txt
> > Address: KFKI Research Institute for Particle and Nuclear Physics
> >         H-1525 Budapest 114, POB. 49, Hungary
> >
> > --
> > Linux-cluster mailing list
> > Linux-cluster redhat com
> > https://www.redhat.com/mailman/listinfo/linux-cluster
>
> --
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-- 
Gruss / Regards,

Dipl.-Ing. Mark Hlawatschek
http://www.atix.de/
http://www.open-sharedroot.org/

**
ATIX Informationstechnologie und Consulting AG
Einsteinstr. 10 
85716 Unterschleissheim
Deutschland/Germany



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