Resize root partition (or how to remove the default /home partition) on CentOS 7 online

readme.md

Resize root partition (or how to remove the default /home partition) on CentOS 7 online

This process requires that you are able to ssh OR log in locally using the root user account and that no services be running as users out of /home on the target machine.

The examples are from a default installation with no customization-you NEED to know what you're working with for volumes/partitions to not horribly break things.

By default, CentOS 7 uses XFS for the file system and Logical Volume Manager (LVM), creating 3 partitions: /,/home and swap.

NOTE: If you want to be sure that nothing is writing to /home you can either modify the host to boot into single-user mode OR try to use the systemctl isolate runlevel1.target command to switch (not tested! should work).

Step 1 - Copy /home Contents

To backup the contents of /home, do the following:

mkdir /temp
cp -a /home /temp/

Once that is finished at your back at the prompt, you can proceed to step 2.

Step 2 - Unmount the /home directory

umount -fl /home

Step 3 - Note the size of the home LVM volume

We run the lvs command to display the attributes of the LVM volumes

lvs

Sample output:

  LV   VG Attr       LSize   Pool Origin Data%  Meta%  Move Log Cpy%Sync Convert
  home cl -wi-a----- 406.94g
  root cl -wi-ao----  50.00g
  swap cl -wi-ao----   7.81g

Step 4 - Remove the home LVM volume

lvremove /dev/cl/home

Step 5 - Resize the root LVM volume

Based on the output of lvs above, I can safely extend the root LVM by 406GiB.

lvextend -L+406G /dev/cl/root

Step 6 - Resize the root partition

xfs_growfs /dev/mapper/cl-root

Step 7 - Copy the /home contents back into the /home directory

cp -a /temp/home /

Step 8 - Remove the temporary location

rm -rf /temp

Step 9 - Remove the entry from /etc/fstab

Using your preferred text editor, ensure you open /etc/fstab and remove the line for /dev/mapper/cl-home.

Step 10 - Don't miss this!

Run the following command to sync systemd with the changes.

dracut --regenerate-all --force

Can confirm this works on Rocky Linux 9 (CentOS). Only need to substitute /dev/mapper/rl-home for /dev/cl/home and /dev/mapper/rl-root for /dev/cl/root.

Thanks you ,very clear guide !!
I would like to do it also with my CENTOS8 KVM server .
I have only 50G in /dev/mapper/cl-root and only 5G are free .
So there is not enough space to add more machines there ,
while in : /dev/mapper/cl-home I have 504G available ,which is a lot of wasted disk space I am no using .
Just want to make sure all this process is safe .
Could you please tell me , if there is data loss risk on cl-root partition , where all my machines are stored , 10xx

I also want to say a big thank you for providing this guide!
Had one issue with Step5 where adding the number from 'lvs' output didn't work, but the command provided by @BuxtaVonGradec did work.
For anyone using Centos 8.5 converted to Centos Stream, this command worked for me on Step5:
lvextend -r -l +100%FREE /dev/mapper/centos-root

Guys i am getting this message after reboot the server

error getting authority: error initializing authority: could not connect: connection refused (g-io-error-quark, 1)

Any suggestion for this..

Dude I asking you, when you do this, is the root data still available ?

Dude I asking you, when you do this, is the root data still available ?

Everything at / survived without issue for myself.

Dude I asking you, when you do this, is the root data still available ?

Everything at / survived without issue for myself.

Thank you, it's worked like a charm > https://ibb.co/rbTXk49

worked fine until the next reboot, and that was the end of that.

I had troubles with this procedure. After unmounting the /home then trying to remove the LVM the system said:

Logical volume centos/home contains a filesystem in use.

Confirmed. It's working for Centos 8 stream.

Worked on CentOS 9 Stream. Thanks!

you are amazing!! ty <3 <3 <3

I had to use resize2fs

LV VG Attr LSize Pool Origin Data% Meta% Move Log Cpy%Sync Convert
home centos -wi-ao---- 872.69g
root centos -wi-ao---- 50.00g
swap centos -wi-ao---- 7.81g
but when i lvremove /dev/centos/home
error happened
'On step Logical volume centos/home contains a filesystem in use.'
i use centos 7

LV VG Attr LSize Pool Origin Data% Meta% Move Log Cpy%Sync Convert home centos -wi-ao---- 872.69g root centos -wi-ao---- 50.00g swap centos -wi-ao---- 7.81g but when i lvremove /dev/centos/home error happened 'On step Logical volume centos/home contains a filesystem in use.' i use centos 7

Did you try re-running step 2? Did you receive any errors when unmounting it?

Size of logical volume cl/root changed from 50.00 GiB (12800 extents) to 750.00 GiB (192000 extents).
Logical volume cl/root successfully resized.
On Stream Centos 8.2, another server

But i don't running step 9. Because there are still 160 GiB left behind.., it's safe ...?

LV VG Attr LSize Pool Origin Data% Meta% Move Log Cpy%Sync Convert home centos -wi-ao---- 872.69g root centos -wi-ao---- 50.00g swap centos -wi-ao---- 7.81g but when i lvremove /dev/centos/home error happened 'On step Logical volume centos/home contains a filesystem in use.' i use centos 7

Did you try re-running step 2? Did you receive any errors when unmounting it?

No there are no error message when unmounting

@fajarra
This is probably due to being logged in as a user then sudo su as root to run through these steps. Since the users are using the /home filesystem to be logged in, it is currently in use and cannot be deleted - thus your issue. You will have to be absolutely sure no users (that aren't root) are logged in when going through these steps.

@fajarra This is probably due to being logged in as a user then sudo su as root to run through these steps. Since the users are using the /home filesystem to be logged in, it is currently in use and cannot be deleted - thus your issue. You will have to be absolutely sure no users (that aren't root) are logged in when going through these steps.

Exactly-this is why the gist starts with

This process requires that you are able to ssh OR log in locally using the root user account and that no services be running as users out of /home on the target machine.

Thank you, Perfect! It's working for Rocky9.

Really helpful, thank you.

Anyone stuck with /home contains a filesystem in use, I had the same issue and couldn't ssh in as root. What I did was:

1. copy home to temp
2. unmount /home
3. copy /temp/home to /home
4. edit /etc/fstab - remove /home
5. dracut --regenerate-all -f (wasn't sure if to do this now or later, so did both)
6. reboot - now /home should be accessed from the / volume, leaving you free to...
7. lvremove home volume
8. dracut --regenerate-all -f