phpMyAdmin - Error - help me

[JoDaS_04]

I have a error :

phpMyAdmin - Error
Error during session start; please check your PHP and/or webserver log file and configure your PHP installation properly. Also ensure that cookies are enabled in your browser.

session_write_close(): write failed: No space left on device (28)

session_write_close(): Failed to write session data (files). Please verify that the current setting of session.save_path is correct (/var/www/tmp)

My system:
Debian 9

help me pls. =(

 

[Active8]

session_write_close(): write failed: No space left on device (28)

check your storage df-h

 

[JoDaS_04]

And? I don't know what to look at. :O

 

[Active8]

/dev/sda3 is full for 98% , so yeah you have to add more storage

 

[JoDaS_04]

How much more do i need?