Create VM larger than 2TB

[Walter54]

I am currently running Proxmox 6.2-4 and we have 7 VM's in total. The VM's were created
in the GUI and the disk sizes are set to 1TB. Some of the VM's are on lvm-thin storage. We want to enlarge
one of the VM's but the label is DOS and I'm unable to create a new partition or extend the last partition
beyond 2TB because of the DOS label. The Proxmox GUI, however, let me resize the VM to 4TB
(The lvm-thin and local storage are both part of a Physical Volume Group). I expanded the physical VG by
3TB that the lvm-thin storage was in, so the GUI let me expand the VM. However, now I am not able to expand
the filesystem in the VM itself. Can I do anything to expand the filesystem without
re-labeling to GPT without losing data (or backing up & restoring)? Is there someway to include the
added space in the VG into that VM? Also, is there a way to create a VM initially with GPT so the
disk can be larger than 2TB?

 

[grin]

You can safely convert DOS to GPT, even with fdisk. At least I have done it multiple times years ago (it was possibly gdisk but as far as I remember the same functionality is now in fdisk as well), but backing the MBR up (which you should do anyway!) is also really simple.

 

[Inglebard]

Hi,
just for information, I don't know which OS you are running and how the partitioning is done.
If you use linux and have a single partition you may (will ?) encounter an issue with grub.

I recently extend from 2Tb to 3Tb, and unable to boot because grub file were after 2Tb in the disk (after a kernel update) and grub was not able to reach them.

 

[Walter54]

You can safely convert DOS to GPT, even with fdisk. At least I have done it multiple times years ago (it was possibly gdisk but as far as I remember the same functionality is now in fdisk as well), but backing the MBR up (which you should do anyway!) is also really simple.

I am going to clone the VM and try the conversion, although this is Linux and I will have issues booting until grub regenerated. Thanks for the reply! I was hoping to create a new VM with a GPT label but I'm not sure you can do this in Proxmox. Looks like it defaults to DOS

 

[Foster Banks]

Hi,

has anyone managed to get this done?
I am trying to create a VM with 5TB from scratch, installation goes well but when the VM tries to boot up, i get a grub error.

I have not been able to find anything that really helps solving this.

Thanks