Proxmox NFS Backup/Remote Snapshots

[n1nj4888]

Hi there,

I currently have some VMs which are hosted on and run from a shared NFS share by the Proxmox hosts.

I currently use Proxmox to backup (snapshot) these VMs back to the NFS share but this seems inefficient with the reads from NFS -> PVE host and writes back from PVE -> NFS host.

Given the NFS host is a Synology running BTRFS and supporting local snapshots, I wondered:

(1) Can I simply snapshot the qcow2/raw using synology without having to stop / freeze / shutdown the running VM on the Proxmox host or could this cause data inconsistencies in the snapshot if ever I have to restore the snapshot?

(2) If I can use the snapshot on the synology but should stop / freeze / shutdown the running VM first, is there a recommended way to do this at a certain time? For example, could I write a script to run on the NAS that connects to the PVE host, freezes the VM, Snapshots it on the synology and then unfreezes the VM?

Thanks!

 

[wolfgang]

Hi,

Generally keep in mind a snapshot is not a backup and you should keep one backup on a different system.
The external System could be an external HDD.

(1) Can I simply snapshot the qcow2/raw using synology without having to stop / freeze / shutdown the running VM on the Proxmox host or could this cause data inconsistencies in the snapshot if ever I have to restore the snapshot?

To have a consistent VM FS you have to turn off the VM.
You have to ensure that the VM kernel cache is empty to have a consistent snapshot.

(2) If I can use the snapshot on the synology but should stop / freeze / shutdown the running VM first, is there a recommended way to do this at a certain time? For example, could I write a script to run on the NAS that connects to the PVE host, freezes the VM, Snapshots it on the synology and then unfreezes the VM?

The correct way to do a proper snapshot is.
1.) call qemu-guest-agent to freeze the fs
2.) if the agent approves the freeze make the snapshot
3.) unfreeze the fs with qemu-guest-agent
Yes, you can write a script for that

 

[n1nj4888]

Thanks for the detailed answer! I’ll take a look around for example scripts and give it a shot!

Thanks again!