Red Hat

file system is full ..even though file is deleted?

Probably a process is still using the content of the file..

You can find it using

Code:

# lsof | grep "(deleted)" # (or lsof | grep (filename))

If it's safe to do so, take the pid from the lsof command, and do:

Code:

# ls -l /proc/(pid)/fd # to get the fd# for the file
# > /proc/(pid)/fd/(fd#) # to empty the file.

Otherwise the space will be freed when the application using it closes, or the system restarts.

# implies a root prompt, meaning your sysadmin needs to do this.

(S)he will need to install lsof if it's not already installed.

Many new-to-UNIX administrators trick themselves like this.

Instead of deleting, truncate, or the contents of a busy file will remain on disk until the process using them is closed.

Exactly.

But even that doesn't always work.

If the file is still being written to, depending on exactly how the file is being written to, what flags were used to open the file, and the specifics of the underlying file system, a single write to the file could cause it to balloon right back up in size.

And then there are the file systems than have snapshots....

Not usually. Most UNIX filesystems have 'sparse' files... You can open a new file, seek ahead 99 gigabytes, and write 1 byte there, to get a file that looks like 99 gigabytes in ls, but only takes 512 bytes on disk. The 99 gigabytes of empty space are not stored.

The same happens when you truncate a file, and they keep writing at the far end. It'll look funny, but you're no longer out of disk space.

You may have problems reading or copying such a file of course, since most programs will just blithely read the sparse sections.

But I think you cannot truncate a file that has been opened for writing. I know you can truncate a file that is being appended to (O_APPEND) ( but not with >> in classic Bourne shell )