Extending a Linux Logical Volume
After setting up my KVM system, I quickly realized that the 1Tb hard drive I was using for KVM-related files wasn't going to cut it, so I bought a 4Tb drive to go along with it.
Inserted the new drive, and booted up the system.
Prechecks
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Before changing anything, dump the current config of the LVM VG, named
kvm-vgsudo vgdisplay kvm-vg --- Volume group --- VG Name kvm-vg System ID Format lvm2 Metadata Areas 1 Metadata Sequence No 2 VG Access read/write VG Status resizable MAX LV 0 Cur LV 1 Open LV 1 Max PV 0 Cur PV 1 Act PV 1 VG Size 931.51 GiB PE Size 4.00 MiB Total PE 238467 Alloc PE / Size 238467 / 931.51 GiB Free PE / Size 0 / 0 VG UUID 4F1YAS-cprX-inKs-eMdp-5aYy-tfCx-e6oAmB -
Check to make sure the newly inserted drive is recognized:
sudo fdisk -l [sudo] password for tom: <snip> Disk /dev/sdc: 3.65 TiB, 4000787030016 bytes, 7814037168 sectors Disk model: WDC WD4003FRYZ-0 Units: sectors of 1 * 512 = 512 bytes Sector size (logical/physical): 512 bytes / 4096 bytes I/O size (minimum/optimal): 4096 bytes / 4096 bytes Disk /dev/mapper/ubuntu--vg-ubuntu--lv: 200 GiB, 214748364800 bytes, 419430400 sectors Units: sectors of 1 * 512 = 512 bytes Sector size (logical/physical): 512 bytes / 512 bytes I/O size (minimum/optimal): 512 bytes / 512 bytes Disk /dev/mapper/kvm--vg-kvm--lv: 931.52 GiB, 1000203091968 bytes, 1953521664 sectors Units: sectors of 1 * 512 = 512 bytes Sector size (logical/physical): 512 bytes / 4096 bytes I/O size (minimum/optimal): 4096 bytes / 4096 bytes -
Erase the current partition table on the drive, not necessary, but I still do it, just to be safe:
sudo dd if=/dev/zero of=/dev/sdc bs=512 count=1 1+0 records in 1+0 records out 512 bytes copied, 0.00103809 s, 493 kB/s
Use LVM commands to add the disk
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Create a Physical Volume from the new drive:
sudo pvcreate /dev/sdc Physical volume "/dev/sdc" successfully created. -
Extend (add) the new drive to the Volume Group:
sudo vgextend kvm-vg /dev/sdc Volume group "kvm-vg" successfully extended -
Display the Volume Group, after adding the new drive:
sudo vgdisplay kvm-vg --- Volume group --- VG Name kvm-vg System ID Format lvm2 Metadata Areas 2 Metadata Sequence No 3 VG Access read/write VG Status resizable MAX LV 0 Cur LV 1 Open LV 1 Max PV 0 Cur PV 2 Act PV 2 VG Size <4.55 TiB PE Size 4.00 MiB Total PE 1192328 Alloc PE / Size 238467 / 931.51 GiB Free PE / Size 953861 / <3.64 TiB VG UUID 4F1YAS-cprX-inKs-eMdp-5aYy-tfCx-e6oAmB -
Add the new drive to the Logical Volume, specifying to use all the space on the drive:
sudo lvm lvextend -l +100%FREE /dev/kvm-vg/kvm-lv Size of logical volume kvm-vg/kvm-lv changed from 931.51 GiB (238467 extents) to <4.55 TiB (1192328 extents). Logical volume kvm-vg/kvm-lv successfully resized. -
Resize the ext4 file system:
sudo resize2fs -p /dev/mapper/kvm--vg-kvm--lv resize2fs 1.45.5 (07-Jan-2020) Filesystem at /dev/mapper/kvm--vg-kvm--lv is mounted on /kvm; on-line resizing required old_desc_blocks = 117, new_desc_blocks = 583 The filesystem on /dev/mapper/kvm--vg-kvm--lv is now 1220943872 (4k) blocks long. -
Verify the newly expanded file system shows up:
df -h Filesystem Size Used Avail Use% Mounted on udev 126G 0 126G 0% /dev tmpfs 26G 2.0M 26G 1% /run /dev/mapper/ubuntu--vg-ubuntu--lv 196G 101G 86G 54% / tmpfs 126G 0 126G 0% /dev/shm tmpfs 5.0M 0 5.0M 0% /run/lock tmpfs 126G 0 126G 0% /sys/fs/cgroup /dev/sda2 976M 107M 803M 12% /boot /dev/loop0 56M 56M 0 100% /snap/core18/1944 /dev/loop1 56M 56M 0 100% /snap/core18/2066 /dev/loop3 33M 33M 0 100% /snap/snapd/12057 /dev/loop2 70M 70M 0 100% /snap/lxd/19188 /dev/loop4 68M 68M 0 100% /snap/lxd/20326 /dev/loop5 33M 33M 0 100% /snap/snapd/12159 /dev/mapper/kvm--vg-kvm--lv 4.5T 133G 4.2T 4% /kvm tmpfs 26G 4.0K 26G 1% /run/user/1000