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Asked: 2024-09-27T01:55:35+05:30 In:

How can I adjust the size of a logical volume in Ubuntu?

I’ve been diving into Ubuntu and trying to get the hang of managing my disk space, but I’ve hit a bit of a snag. So, I’ve set up a logical volume for my files, and it seemed like a great idea at the time. The problem is that I initially allocated way more space than I actually need, and now I’m scratching my head wondering if there’s a way to shrink the logical volume.

I’ve heard that adjusting logical volumes is one of the perks of using LVM (Logical Volume Manager), but I’m not sure where to start. I’ve come across a few tutorials that explain how to enlarge a volume, but they kind of gloss over the shrinking part. I mean, I don’t want to mess anything up and lose my files in the process.

My current setup isn’t terribly complicated. I’ve got an Ubuntu server running some basic stuff, and I want to reclaim that excess space for a different volume that I could use for backups or maybe a small virtual machine. It seems silly to just let the space sit there when it could be put to good use elsewhere.

Is there a safe way to adjust the size of an existing logical volume in Ubuntu? I guess I’m mainly looking for step-by-step guidance, or at least some best practices, because I really don’t want to play the guessing game here. I’ve heard mention of the `lvreduce` command but honestly, that sounds a bit daunting because I don’t want to lock myself into something irreversible.

Also, what about the filesystem itself? Do I need to resize that too before or after I make any changes to the logical volume? I just want to ensure that everything runs smoothly and that I don’t accidentally corrupt anything. If anyone has gone through this process before and can share their insights or tips, I would really appreciate it! Your wisdom could save me from a lot of headaches. Thanks!

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    2 Answers



    1. Resizing LVM on Ubuntu


      Shrinking a Logical Volume on Ubuntu

      If you’re looking to reclaim some space from your logical volume, you can totally do that with LVM. It’s not as scary as it sounds! Here’s a step-by-step guide to help you out:

      Step 1: Backup Your Data

      Before you start, it’s super important to back up your data! Just in case something goes wrong, you want to ensure your files are safe.

      Step 2: Check Filesystem Integrity

      You’ll want to check the filesystem to make sure everything’s in good shape before resizing:

      sudo e2fsck -f /dev/yourvg/yourlv

      Step 3: Resize the Filesystem

      After checking that everything is okay, you can resize the filesystem to a smaller size. Decide how much you want to shrink it by (let’s say you want to shrink it to 15GB):

      sudo resize2fs /dev/yourvg/yourlv 15G

      Step 4: Shrink the Logical Volume

      Now comes the part where you actually shrink the logical volume. Use the lvreduce command, but be careful to specify the new size that you just used for the filesystem:

      sudo lvreduce -L 15G /dev/yourvg/yourlv

      Make sure to double-check the path to your logical volume!

      Step 5: Resize Filesystem Again (if needed)

      Sometimes, it’s a good idea to check the filesystem again after shrinking:

      sudo e2fsck -f /dev/yourvg/yourlv

      If everything went smoothly, you might not need this step, but it’s good practice!

      Step 6: Confirm the Changes

      To check if everything went as planned, you can use:

      lvdisplay

      This will show you the current size of your logical volume and help you confirm that everything looks right.

      Note: Be cautious with lvreduce! If you go smaller than the space used in the filesystem, you could lose data. Always back up first!

      With this process, you should be able to shrink your logical volume safely. Good luck, and don’t hesitate to reach out if you have any more questions!



    2. Yes, it is definitely possible to safely shrink a logical volume in Ubuntu using LVM, and it is essential to follow a few important steps to ensure you don’t lose any data in the process. Before you begin, the first thing you should do is back up any important data on the logical volume. Once you have confirmed your data is backed up, you’ll need to resize the filesystem to be smaller than the logical volume’s new desired size. You can use the `resize2fs` command for this if your filesystem is ext4 or ext3. First, unmount the logical volume using `umount /path/to/mountpoint`, then run `resize2fs /dev/yourvg/yourlv newsize` to shrink the filesystem. Make sure to specify a size that is less than the intended size of the logical volume after shrinking.

      After the filesystem has been successfully resized, you can proceed to use the `lvreduce` command to actually reduce the size of the logical volume. This command would look something like `lvreduce -L newsize /dev/yourvg/yourlv`. Be cautious with this step; ensure that `newsize` is greater than the size you just set for the filesystem. Once you execute the command, you can check the size of your logical volume using `lvdisplay` to confirm the changes. Finally, you can remount your volume and continue using it. It’s worth noting that while shrinking logical volumes and filesystems is entirely possible, there’s always some risk involved, so ensure to take proper backups and proceed cautiously.


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