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Asked: 2024-09-27T13:59:49+05:30 In:

How can I use zerofree on Ubuntu 18.04 to reclaim free space on my disk?

I’ve been trying to figure out how to reclaim some free space on my Ubuntu 18.04 system, and I stumbled across this tool called “zerofree.” Honestly, I’m a bit confused about how exactly to use it effectively. I know it’s supposed to help with deleting empty blocks on a filesystem so that I can actually recover that space, but I’m a little lost on where to start.

So here’s my situation: I’ve been running my Ubuntu for a while, and I like to keep everything organized, but I keep hitting this wall of running low on disk space. I’ve done some cleaning—like removing old packages and clearing out cache—but I still feel like there’s a bunch of space just sitting there uselessly because it’s “free” but not actually available for new files. I heard that zerofree can help clear that up, but I’m not too sure about the specifics.

I’ve read that you need to use it on unmounted filesystems or something like that, which freaked me out a bit. I can’t afford to turn off my computer for long since I’m constantly using it for work, so how can I even manage that? Do I need to boot from a live USB to use it? And what about the potential risks? I mean, I really don’t want to mess anything up—my files are important to me!

Also, after I run zerofree, is there some sort of additional step I should take to make sure the free space is actually reclaimed? Like running fstrim or something? I’ve heard some things about that, but I’m not quite sure when and how to implement it after zerofree.

If anyone has gone through this process or can share some straightforward steps (maybe even some dos and don’ts?), I would really appreciate it. It’s a bit overwhelming, and I want to make sure I’m doing it right without ending up with a messed-up system. Thanks!

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    2 Answers

    1. “`html

      Zerofree is a utility designed for reclaiming space on ext2/ext3 filesystems by identifying and clearing out empty blocks. To use it effectively in Ubuntu 18.04, you must first ensure that the filesystem you want to operate on is unmounted. This means you can’t run it on your main system drive while the system is running, which is indeed a concern for those who rely on their machines for work. A common approach is to boot from a live USB stick that has Ubuntu on it. Once you boot into the live environment, you can open a terminal and run sudo zerofree /dev/sdX, replacing /dev/sdX with the appropriate partition (like /dev/sda1 for your root filesystem). Before doing any of this, it’s essential to back up your data to avoid any unintended loss, especially if you’re not familiar with command-line operations.

      After running zerofree, the next step to ensure the reclaimed space is recognized is to invoke the fstrim command, which is particularly useful for SSDs. You can run sudo fstrim /mount/point to discard any blocks that are not filled. Just ensure the relevant filesystem is correctly mounted again if you had previously unmounted it. It’s wise to read through the manual pages for both zerofree and fstrim (man zerofree and man fstrim) for detailed options and handling specifics. Do avoid running zerofree on a mounted filesystem, as this can lead to data corruption, and take care when specifying device names to prevent running commands on the wrong partition. Always ensure your critical files are backed up before proceeding with operations that modify disk structures.

      “`






    2. Using Zerofree on Ubuntu 18.04

      Using Zerofree to Reclaim Space on Ubuntu 18.04

      So you want to free up some disk space using zerofree? No worries, I’ll help break it down for you!

      What is Zerofree?

      Zerofree is a tool that helps clear out empty blocks on a filesystem. This can be helpful if you have a lot of deleted files that aren’t completely removed, making it seem like you’re running out of space.

      Before You Start: Backup!

      First things first—make sure you back up your important files! Just in case something goes wrong, you’ll want to be safe.

      Using Zerofree

      1. Unmount the filesystem: You can’t run zerofree on a mounted filesystem, which means you’ll need to boot from a Live USB to access it. This might seem daunting, but it’s pretty easy!
      2. Create a Live USB: Download an Ubuntu ISO and use software like Rufus (for Windows) or the Startup Disk Creator on Ubuntu to create a bootable USB.
      3. Boot from the Live USB: Restart your computer and boot from the USB. You may need to change your boot order in BIOS/UEFI.
      4. Run Zerofree: 

        sudo zerofree /dev/sdXY

        Make sure to replace /dev/sdXY with your actual unmounted partition (like /dev/sda1).

      Post-Zerofree Steps

      Once you’re done with zerofree, you may want to run fstrim to help the system recognize the newly freed space:

      sudo fstrim /dev/sdXY

      Do’s and Don’ts

      • Do: Backup your important data!
      • Do: Make sure to unmount the filesystem before running zerofree.
      • Don’t: Run zerofree on a mounted filesystem—it could mess things up!
      • Don’t: Panic! Follow the steps and you’ll do great!

      Risks

      As with any filesystem operation, there’s a small risk involved, especially when messing around with partitions. Just make sure your backups are in place, and you should be fine!

      Hopefully, this helps clarify how to use zerofree without freaking out too much. Good luck with reclaiming that space!


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