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I ran out of disk space the other day (quite common on this particular computer). As usual I started to delete files and directories to restore a bit of space.

However this time the file system still reports that I don't have any disk space available.

Here's what df reports:

replicant:~# df -h
Filesystem            Size  Used Avail Use% Mounted on
/dev/md1              687G  672G     0 100% /
tmpfs                 250M     0  250M   0% /lib/init/rw
udev                   10M  716K  9.4M   7% /dev
tmpfs                 250M     0  250M   0% /dev/shm
overflow              1.0M  1.0M     0 100% /tmp

If I'm calculating this right I should have approximately 15GB available on /. Can anyone explain this to me? It's not just df calculating this incorrectly because I can't create files or anything on the file system.

I'm running ext3 on Debian 5.0.

Michas
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Fred Asp
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4 Answers4

5

Your filesystem has space reserved which is available only for use by the root user. This is fairly standard on Unix / Linux systems, where log files and other files required to allow the system to run are owned by the root user.

You can use the tune2fs tool to query or adjust the amount of space reserved for root.

Run:

tune2fs -l /dev/md1

To see the current parameters, look for a line such as:

Reserved block count: XXXX

This will tell you how many blocks are reserved. Take this value and multiply by the value on the Block size: YYYY line to see the amount of reserved space in bytes.

You can adjust the amount of reserved space with:

tune2fs -m 2 /dev/md1

To set the reserved space to 2%. The default is 5%. These commands must be executed as root, either via a root login of via sudo.

NOTE: Take care when using this command, as improper use can damage your filesystem!

Mike Insch
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Two other possible reasons that no space has been freed:

  • The files you deleted are still opened by some program. As long as a program has an open file (descriptor), the file isn't actually deleted (although it's not available anymore to new programs).
  • The space immediately gets filled up by other files, for example logfiles in /var/log due to a process that is generating lots of messages, e.g. debugging output or errors.
Jaap Eldering
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You have to look what takes up the space on the root partition. First step would be:

cd /
du -sk * |sort -n

This helps you to identify the biggest directories (probably /home or /var). Then repeat the above for the biggest directories. If you remove something, you should compare disk usage before and after, because some program may have files opened. If in doubt, you can use lsof to check it out. If your space is taken by log files, then you should revise /etc/logrotate.conf and run '/usr/sbin/logrotate /etc/logrotate.conf'. This will take care of programs that might have log files opened.

If the above does not help. Boot to single user mode and run fsck, there might be a filesystem corruption as well.

JooMing
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It sounds quite stupid, but have you made sure that you've emptied out your trash-can?

Sometimes when you delete files, the OS will store them in your trash-can in case you accidentally deleted the file, and only truly delete them once you've told it to Empty the Trash.

Try running fsck to make sure that the drive isn't corrupted. You may be occupying all the space with corrupted lost+found files.

akseli
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