Tips for deleting very large files in Linux

Usually, to delete a file in the Linux terminal, we use the rm command (delete file), shred command (securely delete file), wipe command (securely erase file) or secure-deletion toolkit (a secure file deletion tool gather).

We can use any of the above tools to process relatively small files. If we want to delete very large files/folders, say about 100-200GB, it is not as simple as you think in terms of the time it takes to delete the files (I/O scheduling) and the RAM usage.

In this tutorial, we will explain how to delete large files/folders efficiently and reliably in Linux.

Our main goal is to use a technique that does not slow down the system when deleting large files and uses a reasonable amount of I/O. We can achieve this using the ionice command.

ionice is a useful program that can set or get the I/O scheduling level and priority of another program. If no parameters are given or only the -p parameter is given, ionice will query the current I/O scheduling level and priority of the process.

If we give the command name like rm command, it will run this command with the given parameters. To get or set scheduling parameters, specify [PID of process] as follows:

# ionice -p PID

To specify a name or a number for the schedule, use the following command (0 means none, 1 means real-time, 2 means best effort, 3 means idle).

The following command indicates that rm will belong to the idle I/O level and will only use I/O when other processes are not using it:

---- Deleting Huge Files in Linux -----
# ionice -c 3 rm /var/logs/syslog
# ionice -c 3 rm -rf /var/log/apache

If there is not a lot of idle time in the system, then we want to use the best effort scheduling level, and use low priority:

# ionice -c 2 -n 6 rm /var/logs/syslog
# ionice -c 2 -n 6 rm -rf /var/log/apache

Note: To use a secure method to delete large files, we can use the previously mentioned shred, wipe, and different tools from the secure-deletion toolkit instead of the rm command.

For more information, consult the ionice man page:

# man ionice 

That’s it! Are there any other methods in your mind? Share it with us in the comment box.

About the Author:

Aaron Kili is a Linux and F.O.S.S enthusiast, future Linux sysadmin and web developer, currently a content creator at TecMint who loves working with computers and believes in sharing knowledge.

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