Q:

php session_start() permisson denied

PHP Notice:  session_start(): ps_files_cleanup_dir:
  opendir(/var/lib/php5) failed: Permission denied

I am getting it in my apache error log
/var/lib/php5 owner and group is root, so is it fine to change the group to www-data, since its on a production server please help me out

A:

Yes. It's fine. 
Webserver have to write somewhere sessions files. You can change this path in the php.ini file.

