[imp] Horde/IMP performance problems

[Michael Menge]

Hi,

Quoting Jochen Roderburg <Roderburg at uni-koeln.de>:

> Hello IMP Users,
>
> We have been using the older generation of the system (Horde2/IMP3)  
> for many years as our university Webmail system without needing any  
> special optimizations despite a growing number of users.
>
> But when I now tried to offer the current generation (the whole  
> Horde Groupware Webmail Edition 1.2.6) to our users, we had  
> immediately severe performance problems and had to cancel the action  
> after 2 days.
>
> This system now seems to have an enormously increased need of  
> resources as compared to the old version.
>
> Have others made similar experiences?

We had to optimize our system several times because of growing number
of users, changed usage (more shares) and increased need of resources
in newer horde versions. At the moment we have 42249 user in Horde
and up to 1200 concurrent sessions and 1,8 GB Database.

We are running a HA/LB cluster of two servers (2x quadcore XEON E5420
2,5GHz, 16 GB ram each)

ClusterIP is used to distribute the load between the servers.
- eAccelerator to speed up php,
- Memcache for caching,
- tempfs and Memcache for Sessions.
- PgPool is used to keep the two PostgreSQL databases in sync,
   it will eat up most of the performance gained by the second server,
   but removes the single point of failure.

Most of the tweaking was done at the database config. But as you uses
MySQL I can't help much here. Have a look at the Horde- and IMP Archives


>
> Have you had success with the recommendations in  
> horde/docs/PERFORMANCE in such a situation?

It is a good starting point. The List Archives contain some other
hints to look at. After that you have to find the bottleneck.

>
> Does anybody have or know tools which can simulate the load of  
> hundreds of IMP users in order to see the impact of changes?

I'd like to have such tools too ;-)



--------------------------------------------------------------------------------
M.Menge                                Tel.: (49) 7071/29-70316
Universität Tübingen                   Fax.: (49) 7071/29-5912
Zentrum für Datenverarbeitung          mail:  
michael.menge at zdv.uni-tuebingen.de
Wächterstraße 76
72074 Tübingen
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