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

[Kadlecsik Jozsef]

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
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