Resize VM Disk

Draft

This article is a draft. It only tells you how to increase a disk, and only if the disk is partitioned in a certain way. Also not tested by anyone else yet. (other then by the author of this article: Wouter)

Intro

When a virtual machine (VM) needs more disk space, you can expand its storage by resizing the disk in the Proxmox GUI and then adjusting the partition inside the VM using Linux commands. These steps only work if the root partition is at the end of the disk. (The automated install config/preseed ensures this)

Step 1

Before making any changes, you can confirm the current size of your disk. running `fdisk -l /dev/sda`, this lists partition table details of /dev/sda, showing its total size and partitions.

Next, to increase the disk 'physical' size:

• On Proxmox web gui: Select your VM then Hardware > Hard Disk > Disk Action > Resize

Hardware > Hard Disk > Disk Action > Resize

• Enter the new disk size and click OK

After resizing in Proxmox, check if the disk size change is recognized by the system by running `fdisk -l /dev/sda` again The total disk size should reflect the increased value. However, partitions remain unchanged. This means the top layer is aware of the size increase now we need to inform the other layers.

If the total disk size does not show an increase as expected, you may need to run `partprobe` to force the system to re-read the partition table without requiring a reboot.

Step 2

To increase the disk partition:

• In the VM, first get the partition table for info (Assuming the disk is /dev/sda) with `fdisk -l /dev/sda | grep ^/dev`

Output should something like this:

• Resize using 'parted':

 * parted /dev/sda
 * print
 * resizepart 2 100%
 * quit

This is assuming that you need to resize /dev/sda2 (which the 'print' will help you determine)

Step 3

To increase file system's size:

• 'resize2fs /dev/sda2' (Assuming you need to increase /dev/sda2)