[Dovecot] A large number of imap processes

Claude Frantz claude at pc0312b.rz.unibw-muenchen.de
Fri Apr 25 07:27:09 EEST 2008

Timo Sirainen wrote:

> Yes, the main benefit of deliver with Maildir is when it updates the
> cache file, but v1.0 deliver doesn't do that.

Oh ! Very interesting. I did think, that this function was already 
available in the version 1.0.

>> NFS is still a problem.
> Do you use a single Dovecot server or multiple? v1.1's NFS support for
> multiple servers is a lot better than with v1.0.

At the present time, there is only one server but it is intended to have 
multiple ones in the future.

Please allow me to report that it is difficult to predict what the 
setting of "mmap_disable" will produce, from the performance point of 
view. In the case of the system about which I was reporting from, the 
"yes" setting performs really better. It is a large system, having 4 
processors, 8 GB of RAM, a large local RAID system attached and a rather 
large external file store via NFS. There are more than 5000 accounts and 
usually 600 to 1200 users using IMAP, POP3 and squirrelmail, at the same 
time. In contrast, on a very small system, having few accounts, small 
RAM and small local disk space, the "no" setting performs better.

Thanks a lot, Timo !

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