Any news ?
After some research I might have found the culprit…
A while ago I tested xCache 3.0.1 with variable cache and got alot of crashes so I reverted to xCache 2 with variable cache deactivated.
Since then the server has been stable and we have been gradually adding sites.
My theroy is that for some reason xCache can not cope with 1GB of cache.
When I put more that 1GB xCache would not start but even though it would run with 1GB of cache it caused PHP to crash when it went over a certain amount of memory.
My guess is that when I had variable cache activated it hit the 1GB faster and this caused my crashes.
I've set it to 600MB (16 * 37,5 MB) and it seems fine. Before I had it at 1024MB with 32 * 32MB.
This server's got alot of available memory (over 150GB free at the moment).
Touch wood, I have't had any problems since but I didn't have problems every day before so it's a bit early to be shure.
If this is the case, any idea why xCache can't cope with much memory ? Or is it maybe I was using to may caches (32 threads but 16 real cores). ?
I will try and ask around to understand why this is happening. I would rearly like to have 20GB of ram dediaceted to variable cache… 600MB is enough for oopcode caching but not for variable cacheing.