Adding Disk Space to an CentOS VM

This post is mostly a reminder to my future self how to do this!

1. Update the virtual disk

   This is the easy part - shut down the VM and expand the disk size in the virtual machine settings. Easy peasy.

2. Install growpart

   If not already installed, grab growpart.

   1
    $ sudo yum install cloud-utils-growpart
   

3. Expand the partition

   I found the name of my device using the Disks appliction. In my case the root partition was on /dev/nvme0n1p3, so the device is /dev/nvme0n1 and the partition is 3.

   Using growpart (first with -N to do a dry-run):

   1
    $ sudo growpart /dev/nvme0n1 3 -N
   

   If no errors, run again without the -N option.

4. Expand the physical volume

   1
   2
   3
   4
   5
   6
   7
   8
   9
    $ sudo pvresize /dev/nvme0n1p3
    Physical volume "/dev/nvme0n1p3" changed
    1 physical volume(s) resized or updated / 0 physical volume(s) not resized
    $ sudo pvs
    PV             VG Fmt  Attr PSize  PFree 
    /dev/nvme0n1p3 cs lvm2 a--  48.41g 30.00g
    $ sudo vgs
    VG #PV #LV #SN Attr   VSize  VFree 
    cs   1   2   0 wz--n- 48.41g 30.00g
   

5. Expand the logical volume

   Using the output from vgs above (you can also find the name from the Disks application), we can now expand /root:

   1
   2
   3
   4
   5
   6
   7
   8
   9
   10
   11
   12
   13
   14
    $ sudo lvextend -r -l +100%FREE /dev/cs/root
      Size of logical volume cs/root changed from 16.41 GiB (4201 extents) to 46.41 GiB (11881 extents).
      Logical volume cs/root successfully resized.
      meta-data=/dev/mapper/cs-root    isize=512    agcount=4, agsize=1075456 blks
               =                       sectsz=512   attr=2, projid32bit=1
               =                       crc=1        finobt=1, sparse=1, rmapbt=0
               =                       reflink=1    bigtime=0 inobtcount=0
      data     =                       bsize=4096   blocks=4301824, imaxpct=25
               =                       sunit=0      swidth=0 blks
      naming   =version 2              bsize=4096   ascii-ci=0, ftype=1
      log      =internal log           bsize=4096   blocks=2560, version=2
               =                       sectsz=512   sunit=0 blks, lazy-count=1
      realtime =none                   extsz=4096   blocks=0, rtextents=0
      data blocks changed from 4301824 to 12166144
   

   Verify:

   1
   2
   3
   4
   5
   6
   7
   8
   9
   10
   11
    $ df -h
      Filesystem           Size  Used Avail Use% Mounted on
      devtmpfs             3.8G     0  3.8G   0% /dev
      tmpfs                3.8G     0  3.8G   0% /dev/shm
      tmpfs                3.8G  9.9M  3.8G   1% /run
      tmpfs                3.8G     0  3.8G   0% /sys/fs/cgroup
      /dev/mapper/cs-root   47G   13G   34G  28% /
      /dev/nvme0n1p2      1014M  251M  764M  25% /boot
      /dev/nvme0n1p1       599M  7.3M  592M   2% /boot/efi
      tmpfs                774M     0  774M   0% /run/user/976
      tmpfs                774M   28K  774M   1% /run/user/1000
   

6. Fill up the disk and repeat!

Helpful resources:

• https://www.unixarena.com/2022/01/how-to-extend-the-root-filesystem-in-rhel-8-centos-8.html/