I have CentOS 9 installed on a system here that used an out of the box partition config on a 1TB drive. It created an LVM partition scheme where it auto allocated like 70 GB for /root partition as XFS, 8 GB for swap, and the remaining space for /home as XFS. I now have a need to create a new partition to add to the volume group, but first I need to shrink the space being used for /home.

I realized XFS cannot be shrunk, so I backup /home and tried to format the partition as EXT4, but I constantly get the following error:

/dev/vg/home is apparently in use by the system; will not make a filesystem here!

I have it unmounted so how is it in use?

mount | grep /dev/vg/home returns no output.

sudo lsof /dev/vg/home gives me this error that I don’t understand when trying to check what processes might be using it:

lsof: WARNING: can't stat() fuse.gvfsd-fuse file system /run/user/1000/gvfs
      Output information may be incomplete.

Here’s what an lsblk outputs:

NAME        MAJ:MIN RM   SIZE RO TYPE MOUNTPOINTS
sda           8:0    0     1T  0 disk 
├─sda1        8:1    0     1G  0 part /boot
└─sda2        8:2    0  1023G  0 part 
  ├─vg-root 253:0    0    70G  0 lvm  /
  ├─vg-swap 253:1    0   7.9G  0 lvm  [SWAP]
  └─vg-home 253:2    0 945.1G  0 lvm