virt-sparsify in Proxmox?

[mlanner]

I have a need to maintain a VM in Proxmox as a template that gets shipped as a .qcow2 or .vmdk disk. However, before shipping it, I'd like to make it as small as possible. During installation of software inside the VM I download fairly large files, which then add a lot of "used" space in the image. I've read about 'virt-sparsify' being a good tool to "trim" down the image size. Does anyone a) have any experience with virt-sparsify, and b) it's not in the Debian repos -- so is there a plan to include it with Proxmox?

 

[mlanner]

I think I found the answer to my own question. It looks like the 'virt-sparsify' is part of the 'libguestfs-tools' package. My only concern now is if it will conflict with any Proxmox package. Hopefully it won't. I'll try to install it on a PVE test host and report back here once I've got that going have done some testing.

 

[manu]

You could use zerofree available in the debian archive to fill the unused block of the partitions with 0. I have not tested yet on Qcow2 disk images, but with vmdk it makes a huge win to reduce the disk size.

Zerodisk requires you to be in single user mode.
You can also try the following scripted approach, whihc works in multi user setups:
https://anonscm.debian.org/cgit/clo...packer-virtualbox-vagrant/scripts/minimize.sh

 

[manu]

I just found https://rwmj.wordpress.com/2010/05/18/tip-compress-raw-disk-images-using-qcow2/ which shows the approach is valide with qcow2 as well.

 

[spirit]

- If you use "move disk" option offline to convert the disk, it'll be sparse (move disk online don't create sparse image)
- you can do a backup/restore
- you can use fstrim inside a vm, if you use virtio-scsi + discard option.

 

[mlanner]

I found that the libfsguest-tools had too many missing dependencies.

Thanks for all the ideas. I'm going to automate the build by running a backup of the image and then restoring it to another VMID. Seems to be the simplest option at this point.