[Labs-l] No space left on device?

[Prolineserver]

Dear all,

I was tracking down why my PHP session data is lost, and I found the
following warning in the error.log:

2014-04-30 19:27:03: (mod_fastcgi.c.2701) FastCGI-stderr: PHP Warning:
 Unknown: write failed: No space left on device (28) in Unknown on
line 0
PHP Warning:  Unknown: Failed to write session data (files). Please
verify that the current setting of session.save_path is correct
(/var/lib/php5) in Unknown on line 0

So, does that simply mean the webservers' drive is full, or that my
storage is full? Or should I point the  session.save_path somewhere to
my data storage?

Regards, Holger