My Moodle installation:
I use Apache on TCP port 80 and IIS on TCP port 81.
Wich PHP accelerator you think I must use?
It is not clear to me whether you are using Apache or IIS. I use Apache, so this only applies to that.
I have not had much luck with eaccelerator nor with zend. Both had issues with pages loading. I moved to APC, but I would occasionally get crashes (which caused Apache to need to reload -- something that took only a second, but still was showing up in the logs.)
Then I moved to xcache http://trac.lighttpd.net/xcache/ 1.02 stable and things have been working really well and are a little faster than APC. I set the cache size to 100MB -- you will want at least 50MB to be sure. This has been very stable. I tried going to the 1.1RC1 and had some problems, so am sticking with 1.02.
I use a tuned version of the XAMPP distribution which is at PHP 5.1.4, but I think the above will probably work for you.
All of this improved peformance by between 50 an 100% for page loads and decreased the burden on the processors so more users could be handled.
Could you give some advice on how you set up the php.ini-file with xcache?
I installed xcache and my php version is 5.1.4 also. No doubt this accelerated pageload, however Apache did crash when I played a scorm-quiz. This is the first time I've ever experienced a crash, so I've uninstalled the xcache for the moment.
Is xcache stable with php5.1.4 or should I go to php5.1.6? Is Moodle stable with 5.1.6?
After reading the threads in this forum I realized that "MaxRequestsPerChild" could be the problem.
So I set MaxRequestsPerChild = 0 and cross my fingers. No problems so far with xcache.
Yes, same here. The other threads of setting MaxRequestsPerChild to a very low number like 20 or 30 seem to apply to Linux systems. What this does is restart a new thread which is different in Windows. And it may be at this time that instability is happening. Setting it to zero means that this never happens. But we should watch to make sure that connections termnate, which one can do by setting up the server-status feature in Apache.
Good luck and let us know if this works.