My /usr folder needs to get moved to a new partition. How can I do this without erasing the contents?

Can this be done while Ubuntu is running, or do I need to use the LiveCD for this?


5 Answers 5


It would be safest to use a Live CD, but you could do:

  • copy all the files to a new partition, making sure that the contents of /usr do not change while you are doing this.
  • edit /etc/fstab so that /usr will be mounted on the next reboot
  • reboot
  • delete the old files

See below for details on each step.

Note that you can't mount the new partition on /usr while running as there will be lots of files in /usr that will be open.

Copying the files

I would use cp -a. -a is the archive option. From the man page:

-a, --archive
          same as -dR --preserve=all
-d     same as --no-dereference --preserve=links
-P, --no-dereference
          never follow symbolic links in SOURCE
          preserve      the      specified      attributes       (default:
          mode,ownership,timestamps),  if  possible additional attributes:
          context, links, xattr, all
-R, -r, --recursive
          copy directories recursively

Editing /etc/fstab

You need to know the UUID of your new partition. You can see the mapping by doing:

$ ls -l /dev/disk/by-uuid/


$ sudo blkid

And then add this line to /etc/fstab:

UUID=634c31a5-e27c-4e33-ac67-2e22491a30c2 /usr           ext4    defaults        0       2

Change the UUID to your UUID, and change ext4 to be the file system type you are using - you should know this if you have set up the partition.

Delete the old files

After the reboot, the old files in /usr on the root partition will be hidden by the new partition mounted on /usr. But we can use some mount bind trickery to get to the old files and then delete them.

$ sudo mount --bind / /mnt
$ sudo rm -rf /mnt/usr/*
$ sudo umount /mnt

But some slight mistyping (say, hitting Enter when you'd only typed sudo rm -rf /mnt ) could cause disaster, so I would only use this method if you were very confident in what you were doing, really couldn't deal with any downtime, or had no physical access to the machine and hence were unable to boot off a live CD or live USB stick.

  • 6
    rsync is so much better suited for this than cp Commented Aug 2, 2010 at 20:17
  • 1
    @MarcoCeppi Could you expand on that? Maybe give a variant answer that uses rsync instead?
    – Kazark
    Commented Dec 31, 2014 at 20:33
  • 8
    Replace cp command with rsync -avz. Rsync allows you to restart copies and should generally be used when moving between partitions, block devices, or machines. Commented Dec 31, 2014 at 21:17
  • 5
    Do NOT use cp. It doesn't preserve HARD LINKS. This will break package upgrades in future. For example /usr/bin/s2p and /usr/bin/psed is the same file. Moving with cp will create 2 independent versions of that file. Do rsync -aH instead. Commented Jun 4, 2015 at 20:55
  • 2
    First of all, skip the -z flag - it enables compression, which given you're not sending the files over a network is useless overhead (except that rsync is usually smart enough to ignore it, but still, might as well drop it). @AleksandarStefanović you definitely want the contents there, not the folder, and the reason it's happened that way is due to some rsync quirks: it treats rsync -avH a/ b differently from rsync -avH a b, copying the contents of folder a (that is, a/*) in the first case and the folder itself in the second. Make sure you use the slash here.
    – Darael
    Commented Apr 7, 2016 at 9:09

Since most libraries that are used are in /usr, I would not recommend to move this directory while running Ubuntu. In fact, you probably get error messages when you try to do this. Hence, the best is to use the LiveCD.

You can use several possibilities to move/copy the files cp, rsync etc. you want to make sure that any symlinks are created and not just copied. cp and rsync both have options for this.

After moving the files to the other partition you need to add another mount in /etc/fstab to mount the new partition to /usr.

  • Some good points. I had to try, impatience getting the better of me. It was interesting that the most visible failure was fonts disappearing represented by boxes instead of characters. Booting an iso image and working with the system offline, essentially, though a hassle, is likely the safest course. Commented May 8 at 22:12

This is how I've done it (following the Hamish's answer and the comments):

  1. Copy all the files the newly created partition (replace with the location of your partition, it should look similar to mine):

     rsync -avz /usr/* /media/aleksandar/750b84e2-e65f-4309-ade5-5af0033a937c 
  2. Edit /etc/fstab (same as in Hamish's answer, of course, replace xxxxxx with your UUID)

     UUID=xxxxxx/usr           ext4    defaults        0       2
  3. Reboot the system

  4. After rebooting, open System Monitor or similar application to see whether your new /usr partition is mounted, and to safety-check whether everything went as planned.

  5. After checking that everything is alright, you can delete your old /usr partition. I will keep mine just in case something goes wrong.

  • 4
    @cmks because I felt like other answers were incomplete - I didn't get complete solution from one answer, and none of the answers didn't have enough detail to them. I felt like users who would come to this question would need help. It doesn't matter if it's five years old if someone still needs the information from this question. Commented Apr 8, 2016 at 13:19
  • 1
    Why is everybody rebooting their system? Shouldn't a sudo mount -a allow it to keep on running? Commented Aug 6, 2016 at 9:01
  • @Hagen I guess it's just for good measure Commented Aug 6, 2016 at 9:04
  • How can I to make step 7, if step 4 was skipped? mount --bind is the answer.
    – vp_arth
    Commented Jul 10, 2020 at 13:12
  • @vp_arth what he means is that he renamed it to /usrBACKUP while the system was still running, and then it crashed. So don't do that. Instead, just reboot the system normally. Don't worry about having two /usr folders, Linux will happily hide the old one and mount the new one in its place. (You can delete the hidden folder, but I'm not explaining that here.)
    – Intrepidis
    Commented Aug 22, 2020 at 9:59

I performed a migration of the /usr partition but I had some issues which I will be detailing in the following lines:

  • issues on /etc/fstab at the moment to mount by UUID (specially when u restart the OS), getting the error UUID specified does not exist.


Linux Distribution: Ubuntu 18 (x86_64)

The steps I performed were the following (/dev/vda will be my new disk):

  • Start the system in Recovery Mode or single user.
  • Validate that non of the files of /usr are being used:
lsof /usr
  • Create the new directory:
mkdir -p /usr_new
  • Create a pvs, vgs and lvs partitions:
pvcreate /dev/vda
vgcreate data_vg /dev/vda
lvcreate -l 100%FREE -n usr data_vg
  • Make a filesystem of the lv partition ( to identify the full path of the lv, execute lvdisplay) and mount the partition to the new directory /usr_new:
mkfs.ext4 /dev/data_vg/usr
mount -t ext4 /dev/data_vg/usr /usr_new
  • Move the content of the usr partition to the new one:
cd /usr
find . -depth -print0 | cpio --null -pvdm /usr_new/
  • Rename the old one and mount to the new one:
mv -v /usr /usr_old
umount /usr_new
mkdir /usr
mount -t ext4 /dev/data_vg/usr /usr
  • Make permanent changes on /etc/fstab file ( add the following line to the end of the file):
/dev/mapper/data_vg-usr /usr    ext4    defaults    0   0
  • Confirm that mounts are working as expected:
mount -a
  • Reboot the system:
init 6


In case you face incidents during the boot for mount incidents, take into consideration the following steps to fix / debug the issue:

  • From the grub options, type e and add the following text after the vmlinuz arguments:

enter image description here

  • Press control + x, and boot from the edited option (the first one most probably)

  • If you are addressed to the initramfs terminal, type the following:

initramfs > chroot /root
  • You will be moved on to your root system partition, from there try to check the content of the /etc/fstab and made the required changes, or return the system like it was before.
$ exit
initramfs > reboot

I needed to move /usr folder from the root partition to a new one, because the disk was full. It was a sort of "temporary" system, so it was ok for me to use an available 16 gig stick, the only thing I could spare at the moment. I recall here the steps I followed, if they are of any help for anyone.

make a new GPT, new ext4 (g, n & w options) on the stick. For me it was on sdd, please be carefull, find which is yours

sudo fdisk -l /dev/sdd

make filesystem

sudo mkfs.ext4 /dev/sdd1

mount somewhere the stick

sudo mkdir /mnt/16G
sudo mount /dev/sdd1 /mnt/16G

copy everything to the stick (-a=keep permissions, -h=human readable) (instead of "cp -r /usr /mnt/16G" use rsync)

rsync -ah --progress /usr /mnt/16G

find the UUID of the stick

sudo blkid

put it in fstab

sudo nano /etc/fstab
    UUID=40xxxx3f-exx8-4xx3-9xxx-xx055xx34xx5 /usr          ext4    defaults        0       2


sudo poweroff

boot with a LiveUsb ubuntu and rename original /usr to something else, like /usr1

create a new empty folder on the root partition and name it "usr", for the stick to be mounted on, as stated in fstab. Otherwise you will get a nice initramfs on next boot (sorry, I haven't tested Hamish Downer's advise for [$ sudo mount --bind / /mnt] [$ sudo rm -rf /mnt/usr/*] [$ sudo umount /mnt])

reboot to the normal installation

Hope I didn't forget or messed up anything!

Edit: You can now remove /mnt/16G and IF everything is nice 'n' smooth, delete the /usr1 to regain the space!

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