df

If df and du give different output of disk usage. Then, most probably it is due to "open file descriptors".

Run `ls +L1` to get a listing of open files that have been unlinked or removed. Note the file size and kill or restart the respective service.

Reference: walkernews.net

Recently, I've had a client who's had issues with uploading files and general functioning of the ISPConfig hosting control panel.

So the first thing I checked out was "/proc/user_beancounters", and everything seemed normal there.

Quick check with `vzquota` turned out that the inodes were maxed out.

Blocks and Inodes can also be checked/displayed within the container via `df -h` and `df -i`.

Additionally, since he had a lot of users, he was maxed out on the users limits too. Noticed that with `repquota -a` which pulled up a huge number of users.

Increasing the appropriate limits with vzctl on diskspace, diskinodes and quotaugidlimit resolved all issues.