How to resize vm disk (decrement)

[m3a2r1]

I've got machine with 1000GB disk but it uses only about 60GB (when I backup it, it's 240GB of data) and I would like to change it to 100GB. It's Windows Server VM so I can shrink it in system. How to shrink it safely in pve?

 

[apoc]

I do it this way (even though usually it is 10-25 GB I reduce)
1. Shrink the filesystem within the guest. I usually go as low as possible (or at least way below the planned size)
2. Then I power off the VM
3 decrease the size of the disk - this usually involves the CLI (or at least I am doing it that way
4. Adjust VM configuration file (/etc/pve/qemu-server)
5. Power on VM
6. Increase partition to maximum size.

By this approach I avoid potential issues in size calculations

 

[m3a2r1]

Ad. 3 - how to do it with CLI?

 

[apoc]

That depends on your storage type.
What are you using?

 

[m3a2r1]

NFS share, qcow2 files.

 

[apoc]

Try following instructions here:
http://woshub.com/kvm-expand-shrink-vm-disk/#h2_2
PS: web search is your friend

 

[m3a2r1]

Thank you. I like especially: What happens after running this command? After starting the server, the system won’t boot

 

[apoc]

Damn it. Haven't read the whole thing through.
But what you always can do in such cases:
Attach a second disk with desired size to your VM and after shrinking partitions DD things over.

 

[m3a2r1]

Don't worry, I'll do it on Monday and I'll let you know how I did it.