How to remove "dead.letter" File which left no free space in root directory

Question

1. Today I noticed that dead.letter file is created in my root directory on one of the EC2 instances.
2. After some look up I came to know that this is created because of some incomplete or terminated email functionality.
3. It has size of 6 GiB and it left no free space in root directory.
4. I have deleted the file still my root directory shows no free space available.

Any idea how to remove this file and free up the root space?

Answer 1

If you have removed it and the space still isn't freed, then it means a process has a file handle opened on it.

Try and find the PID of the process using, for instance:

for process in /proc/[0-9]*; do
    for fd in $process/fd/*; do
        file=$(readlink -f $fd)
        if [ "$file" = "/root/dead.letter" ]; then
            echo $process
        fi
    done
done

Then kill it/them.

Answer 2

You know about lsof (http://linux.die.net/man/8/lsof) ?

In this case:

sudo lsof /root/dead.letter

This prints out info's about the process having the file open. You still have to kill that process.

Answer 3

If the above script does not work, One can just think of the processes which might be having the handle to such files occupying space in root or home directory.

Kill such processes and the disk space will be freed

You can use (ps -ef | grep process_name) to find out the process id.