server unable to store session

[Anon]

I'm using apache, php, mysql on linux, things work well as start, but suddenly the session not working(use to work before yesterday).

It seem like server unable to store session information, I check the session files created by the server and only to find that they are all 0 bytes in size(empty), how can this be happen?

disk space on the server is still available, why server cannot write to the session file?

[dannys]

make sure that the webserver and/or php have permission to write to the directory used to store the session data.

[Anon]

I checked the webserver already, the permission setting is ok. Need to specify permission for PHP? how to do it? I thought PHP is just a module of apache and it's permission setting should just follow the webserver setting?

what else should I check for the problem?