MySQL Error!

The Error returned was:
Can't connect to local MySQL server through socket '/var/run/mysqld/mysqld.sock' (2)

Error Number:

Warning: Unknown: open(/var/www/admin/data/mod-tmp/sess_9o5r0fh94h048rpqgbde19mal1, O_RDWR) failed: No space left on device (28) in Unknown on line 0 Warning: Unknown: Failed to write session data (files). Please verify that the current setting of session.save_path is correct (/var/www/admin/data/mod-tmp) in Unknown on line 0