Some time, our clients have reported that they can't access VestaCP and the website doesn't work. This can be because a number of issues, but generally is due to the disc running out of space because of the webs and backups that generate automatically.
Checking that the issue is on the disc [Basic Level]
The simplest way to detect that the issue is because of disc space lack, you have to acces the VestaCP login panel and click on the button "Start Session" - without inserting user or password-. Inmediately, you should get the error: NO LANGUAGE DEFINDED.
This error indicates that the server has run out of space and can't start session - because for that matter, it needs o create files on the server,- log ones, probably -.
Checking that the issue is on the disc [Advanced Level]
You have to connect through SSH to you server and once connectes, run the following commands:
# df -h
You should see the following output:
You can see that /dev/sda2 is at 100% usage, therefore the disc is full and this is why it can't be started session in VestaCP or some of the services doesn't work properly.
Solving the problem
The best way to solve the problem is resizing your server's disc. This way, adding more space to the disc, once the server is rebooted, it'll work correctly. In case that you have resized and the issue persists, you'll probably have to extend the partitions manually.
Another option, if you don't want to resize the disc - since once resized, is has to keep that size - is erasing the server's content. There are a lot of places where you can make some room. The first one is the directory where VestaCP keeps the backups, located on /backup. In there, you can erase files and make room. You can also do it by erasinf logs in /var/logs.