I am trying to register as a new user on a Symfony 2 project, i've been working on. This popped up all of a sudden. It was working in office yesterday, and I've setup a similar setup at home. I got:
Warning: session_start(): open(/var/lib/php5/sess_ibfocfkgbpfaoimac34nkjotp2, O_RDWR) failed: Read-only file system (30) in /home/projects/notes/app/cache/dev/classes.php line 406
Whats wrong?
The session save handler needs to be able to write on the disk. The file system denies writing. That's causing your issue.
Change the session save path to a writeable directory.
If you're using PHP FPM and have set session_save_path in your pools, make sure you add a forward slash before the directory (absolute URL). This is what the problem was for me.
M running debian jessi and i had the same problem for me a chown -R and a chmod worked