Best practice to make VM backup of windows guest OS in Proxmox environment


New Member
Oct 4, 2022
Currently I am testing Proxmox with the aim of implementing Virtualization in our production environment. Our testing environment consists of 3 Proxmox VE configured as cluster and a backup server based on Proxmox backup software. The virtual environment consists of a number of Windows and linux guests servers. Data backup and data restoration was tested on both linux and windows virtual servers. In all cases operations were successful. Data restores was successful also on file level, both in Linux and in Windows Virtual environments.

As far as I know proxmox backup application does not use shadow copying, so there is a possibility that the backup of a windows VM is not consistent.

So my question is:- what is the best practice in proxmox environment to make a Windows VM backup and the backup remain consistent.
backup consistency can be improved by qemu guest agent (install in vm and activate in vm settings), which will freeze / thaw guest file systems to increase backup consistency

Hi Mnih,

Thanks for your comments and the link. The link addressed most of my concerns and from I could understand the proxmox backup is using the windows VSS service which definitely improve consistency.

The below is intended for proxmox staff and to continue with the discussion.

As explained in the previous post I am evaluating proxmox as alternative solution for VMware and Hyper-v. I really like it, but my main concern was the backup solution for the proxmox virtual environment. Virtual environment solution without robust backup solution is not an option. It is also expected to find Windows based virtual machines in small and medium industries. Hence a robust backup solution for Windows based VM is also important. I searched for answers in the internet and it appears that the backup solution for windows VM on proxmox environment is a common issue.

I tested the proxmox backup server and I like it and its features suite our needs. But my concerns are two

1. The proxmox backup server is relatively new and in my opinion is still on the road to maturity when compared to Veem for example.
2. How reliable a backup of Windows VM is when using the snapshot mode. With reliability I am referring for File level and OS level excluding applications such as database which require specific software for backup.

Any comments are welcome but comments from Proxmox Staff will be helpful to everyone.
Comments on backup strategies already used to backup domain controller or File servers will be appreciated.

I have no issues with regular full snapshot backups of Windows VMs; I make these nightly direct to a NAS storage. Obviously, I can only keep a few copies. I also have another shared storage for weekly snapshot backups, to sync for offsite backups.

My first Proxmox Backup Server also runs nightly backups, but it is an old machine and it has issues sometimes (slow backups, very slow verification tasks). Not recommended.
I now use a much faster server with fast SSDs, 10GBe network, and incremental backups finish quickly.
This allows me to run backup tasks during the day, hourly, and nightly fast verification tasks.

As for reliability you of course need the qemu guest agent on VMs (Windows and Linux); then I find it's very reliable.
I never had issues restoring, but in my experience, Windows might complain after restore and a reboot fixes that (no different than after a power fail on bare metal). For me that's a Windows issue.

To sum up my current strategy:
Weekday nightly backups to NAS (keep 5 copies)
Weekend backups to secondary NAS (keep 4 copies), and sync to offsite cloud storage.
Weekday (6-6) Hourly Incremental backups to Proxmox Backup Server, keeping 24 hourly, 28 daily, 8 weekly, 11 monthly, 2 yearly.


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