Server cpu/disk spikes from update to 11.0.9 to 11.5.30 -- Probably apache

[Pierre-AlexandreT]

Hi,

I've been experiencing major server "freeze" from an update of Plesk 11.0.9 to 11.5.30.
I've also updated my php to 5.4 during the same maintenance.

It happened often and during long periods(30 mins) at the beginning, but successfully reduced it to about twice an hour and during 2-5 mins by disabling drweb and spam assassin(already have spam filter on MX).

During the freeze, cpu ressources are maxed at 100% and disk are working really hard.
Here' a screenshot of some TOP while it happens



I run Plesk on a 4CPU VM with 8GO ram on a vmware infra.
It seems to me than the httpd apache process increase alot during this time while normally really low.

1) Any of you experiencing the same issue?
2) Is there a way to see which domains can cause this problem?
3) Could it be DDOS attacks?

I didn't have this problem while running 11.0.9.

Thank you very much for your help.
Cordially,


** Edit : Also seems to me that memory usage is really low when server restart but seems to increase to the max allocated while time goes by. Could it be a memory release problem -- disk swap.

 

[Pierre-AlexandreT]

After some verifications, it does seem like the problem is caused by disk swapping, which I suspect is the result of a memory leak.

After fresh reboot, Memory is at 1.7G/10G (Increased of 2G since first post).
After 2.5 hours, memory's at 3.5G/10G and still increasing slowly.


It gets messy at 10G/10G and begins to swap//unswap.

Anyone else have experienced this kind of behavior or know what might cause it.
Thank you.