So df is telling me that I'm using 49/59G, so I set out to find my space.$ df -hFilesystem      Size  Used Avail Use% Mounted on/dev/vda1        59G   49G  7.9G  86% /none            4.0K     0  4.0K   0% /sys/fs/cgroupudev            2.0G  4.0K  2.0G   1% /devtmpfs           396M  340K  396M   1% /runnone            5.0M     0  5.0M   0% /run/locknone            2.0G     0  2.0G   0% /run/shmnone            100M     0  100M   0% /run/useroverflow        1.0M     0  1.0M   0% /tmp```I first tried du5.1G    .2.3G    ./var1.3G    ./usr973M    ./var/log834M    ./lib736M    ./lib/modules713M    ./var/lib600M    ./root592M    ./var/log/nginx456M    ./var/wwwNow, I'm no math major, but I'm pretty sure that's not 49G.I tried ncdu, and that's telling i'm using 5GB / 128GB
Where's my space?
ubuntu;disk usage
One cause for this is having files that have been deleted from disk, but are still open in memory. These files although deleted, still report as space taken up on the disk.You can check if you have any files in this state (and also which process is holding them open) with lsof.$ lsof | grep deletedopen.pl 15220 steve 3r REG 8,1 70 56099817 /home/steve/scratch/in.txt (deleted)The 7th column (70 in the above case) is the size of the file in bytes. The first column (open.pl) is the process that's holding the file open. The PID of the process is the second column.Typically this happens when huge log files are removed, but the process that was using them was not restarted.To free this space, simply restart the service that is still holding the file(s) open.