Atomicorp

It was happened yesterday that session cannot be written, so no login on all sites was possible.
After a lot of research was discovered that was mod_security (actually I am not 100% sure) we disabled mod_security work, we enabled it, not work.
LOGS not tell too much, anyone have a hint where to look?

Check your error_log files and also check to see if you have a php log file - these files will normally have the information you need. If you don't know where they are you can usually find them in your vhosts statistics/logs directories. This sounds like a simple permissions problem where you lack the permissions to write to your PHP sessions directories/directory.

Hehe, no is not a simple persmission issue, something was updated (mod_sec or ossec) and after that on an apache restart happened this globally on the whole server, not ONLY for one domain. So in one moment worked and over the night not worked (I suspect again an update of mo_sec or ossec)
I suspect to be some problem in mod_sec, nothing is in error_log or any log (even we activated mod_sec debug level 9)
If you like, we can enable access to server ... is running ASL on it.
You will enable mod_sec and you can see the result.

When you say no sessions can be written, what do you mean? You said there was nothing in your logs, and if thats the case its not modsecurity and I don't understand what the error is.

Can you provide some more information about the error(s) you are experiencing?