Not sure what the issue was but setting the APC shm.size to 48 caused the APC to fail with 500 errors during a high load test. I reset it to 30 and it works fine..
Thats not related to the use of ispconfig, its more a system / kernel issue. I had the same with xcache some time ago on a server without ispconfig. The only solution that I found after searching the net for soome time is to not set the shm size too large.
I am running ispconfig 3 on a Debian perfect server install using fcgid. Should I even use APC with this configuration? Rob
As far as I know, apc creates a new cache for every fcgi process. So apc might speed up php but not as much as it would do it for e.g. mod_php. But my information on that topic is not up to date, so you might want to ask on the apc mailinglist or wherever the apc devs are reachable if apc works with php-fcgi processes as well. Or maybe someone else here has experience with this software combination?
APC will only run well under mod_php so I have switched my sites back to mod_php. Everything is running fine.. Rob
