MySQL Error!

The Error returned was:
Can't connect to local MySQL server through socket '/tmp/mysql.sock' (111)

Error Number:

Warning: Unknown(): open(/tmp/sess_91d91bb9a902a1a81cdf7c5ec026911e, 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 (/tmp) in Unknown on line 0