Resizing VM Disks


before I am starting to look into the VM states diagram and digging into scripts.

the docs describe that resizing vms at vm creation time here:

what does this sentence mean?

  • Increase the size of the disk container prior to launching the VM

the meaning of the second sentence is more obvious to me, it’s actually pretty clear:

  • Using the contextualization packages, at boot time the VM will grow the filesystem to adjust to the new size. This is only available for Linux guests in KVM.

so does “inceasing the size of disk container…” actually mean that it resizes a qcow file (or raw disk image) using qemu-img??

if yes, then this is not supposed to work on storage backends that don’t use qcow2 (or raw images). correct?

maybe someone can point me in the right direction.

thanks and all the best

Hi jojo,

Yes. It means resizing the device/file that is backing the VM disk.

Nope :slight_smile:
It depend on the capabilities of the storage system and its TM_MAD driver.

AFAIK Currently the feature is for NON-PERSISTENT images only. The device resize is done in the TM_MAD/clone script. For CEPH it is here:

For qcow2 it is here:

And for StorPool it is here:

Hope this helps :wink:

Kind Regards,
Anton Todorov

1 Like

Yes Anton, it definitely helps! Great! :slight_smile: Thank you!