More than 1024 Apache / MySQL processes?

[Christian Hammers <ch@westend.com>]

Hello

On one host I have, at peak times, roughly 1000 simultanous Apache
processes which serve MySQL intensive scripts that produce about the
same number of MySQL instances.

As 1000 connections are no longer sufficient, our customer demands a
stronger server but I'm unsure if it's possible at all to have say
1500-2000 connections.

Limitations I am aware of are:
* [compiletime] /usr/include/bits/local_lim.h PTHREAD_THREADS_MAX 
  (default 1024 in woody, 16484 since sarge) affectets at least MySQL
* [compiletime] Apache HARD_SERVER_LIMIT (default 256)
* [compiletime] MySQL suggests to lower the Thread Stack size
* [runtime] ulimit "max user processes", "open files"
* [runtime] /proc/sys/fs/file-max
* [configuration] max_clients in Apache
* [configuration] open_files_limix, max_connections,
  max_user_connections in MySQL

Is there anything else? Has anybody ever tried it? My test machines
sadly have not enough RAM to try it.

bye,

-christian-

P.S.: And yes, better alternatives like clusters etc are already under
      consideration, too, but not so easy to implement :-)

-- 
Christian Hammers             WESTEND GmbH  |  Internet-Business-Provider
Technik                       CISCO Systems Partner - Authorized Reseller
                              Lütticher Straße 10      Tel 0241/701333-11
ch@westend.com                D-52064 Aachen              Fax 0241/911879