Coalesce disks

[Alessandro 123]

Ciao,
this is the situation: multiple VMs migrated from XenServer to PVE, each one with their original disks (i've done an automated migration script that will move virtual disks from XS to PVE).

Almost all of these server has multiple disks connected with A LOT of wasted space. In example: 150GB used space but 400GB disk images.

After moving to PVE and ZFS with qemu, do you know a way to coalesce these dissk images ?
All VMs have LVM on it.

 

[aaron]

how are the VM disks stored? If you enable "discard" in the disk options, the trim/discard command from the VM will be issued to the underlying storage layer and if it supports it, the unused space will be "reclaimed". The storage needs to be thin provisioned and be able to support trim. E.g. Ceph RBD, ZFS (thin provisioned), thin LVM, ...

 

[Alessandro 123]

It' s a standard ZFS install made with the proxmox installer. I don't think it's thin provisoned by default

 

[Alessandro 123]

But one of the biggest issue is how to "merge" multiple disks in a bigger one. Some of my old VMs are made of 7-8 "small" 20-25GB disks, I would like to move on PVE with just one bigger disks, if possible