kolab 2.2

[Ingo Steuwer]

Hi,

Am Donnerstag, 23. Oktober 2008 schrieb Gabriele Di Giambelardini:
> Hi to all, I have a big problem with kolab 2 performance.
> I have an server with 10 GB of RAM and about 150000 users.

Once they are imported into LDAP and the mail-spools are created, the pure 
amount of users should not be the problem, but the number of current users 
and the number/size of deliviered mails. We installed a kolab-based 
mailserver with ~80000 users (mailaccounts) and Horde webmail on a far 
smaller hardware (one server, 2GB RAM) years ago.

> After I imported the user in the kolab ldap the server become very very
> slow, it's impossible use a webmail. so I installed the webmail on other
> server with eaccelerator. But now on my main server the kolab imapd take
> all the CPU and every thing is too slow. The are some settings for imap of
> if somebody know the why of this latency... THANKS

We [1] had trouble with cyrus and horde getting slow in large installations 
because of a very inefficient group-ACL-computing of cyrus. In some cases it 
helps to activate "nscd" with large cache sizes (mhm, I don't know if nscd is 
part of a standard Kolab-distributon?), in other scenarios we deactivated 
this in Cyrus' imapd.conf (unix_group_enable: no) - which is OK as long as 
group ACLs are not required. But this might also be slightly different in 
plain Kolab.

You should try to figure out what the imapd really does. Is it during a login, 
mail-delivery, folder-operations etc.; maybe imapd is only waiting for 
something else (Disk I/O, LDAP, ...)?

Regards
Ingo Steuwer

[1] Please note that we don't use the openpkg-distribution of kolab but a 
derivated installation based on Debian with patches and configurations 
similar to/derived from plain kolab.

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Ingo Steuwer           Projektmanagement        steuwer at univention.de
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