Re: concurrency problem

[Howard Chu <hyc@symas.com>]

Pruebas wrote:
>  Hi, i'm using openldap-2.0.27 in a redhat 9 box.

That's your first problem. OpenLDAP 2.0 was obsoleted 3 years ago. The 
current stable release is 2.2.26, although 2.2.27 is in better shape. 
The latest available release is 2.3.4. You seriously need to upgrade, 
and you should probably complain to your vendor for bundling such 
antiques in their distros.

>  I have installed qmail-ldap, and it the hours of high traffic it
>  can't get a connection to the ldap server, i wrote to the qmail-ldap
>  list, and they toll me that it was a concurrency problem, so I rise
>  the concurrency and the threads to 500, but i still have the same
>  error.

No amount of configuring will make OpenLDAP 2.0 work well in a high load 
environnment.

It is a bad idea to set the threads value to such a high number, 
regardless of the release. At a minimum each thread consumes 2MB of 
stack space, so thats 1GB of RAM eaten up right there. In newer releases 
the stack size per thread is even higher. The optimal number of threads 
depends on the number and type of CPUs in the system, as well as the 
available memory size. The default on newer OpenLDAP releases is 16; 
12-16 per CPU generally works well.
--
 -- Howard Chu
 Chief Architect, Symas Corp.       Director, Highland Sun
 http://www.symas.com               http://highlandsun.com/hyc
 Symas: Premier OpenSource Development and Support