is 2025 Server (ReFS) safe now?

[AndyFearless]

hi all,

been following the ReFS thread for a while now, and wondering if anyone is rolling out 2025 Server as a new Hyper-V host (with ReFS veeam working drives) yet?

I'm still sticking with 2022 for DCs, but have been using 2025 for file servers.

But what about Hyper-V Hosts and B&R Servers/Repos?

any thoughts?

[Mildur]

Hi Andy,

I can’t comment on Hyper‑V specifics — that question would probably be better addressed in the official Microsoft forum.
Regarding Veeam Backup Repository and ReFS, please take a look at KB2792.

I recommend considering the use of a Hardened Repository, especially if you have a hardware server acting as the repository. You’ll benefit from a proven file system and support for immutable backups.
The Backup Server itself can be deployed as a virtual machine on Hyper‑V — either based on Windows or the Veeam Software Appliance.

Best,
Fabian

[PeterC]

Hi Andy,

When we started using Veeam B&R, about 10 years ago we started with Server 2016 and NTFS for our repository servers, later replaced them with Server 2019, back to Server 2016 and ReFS. We have had lot's of performance issues with backups and merging them. Also cleaning up ReFS volumes was an nightmare. 3 years ago we decided to switch to hardened repos with Ubuntu 22.04.
I can only strongly recommend this, the performance gain, ease of use, it is really exceptional. We are now using synthetic full's every weekend, it is really, really fast creating a new full backup we can use.
Hardened repos with XFS has been a game changer for us.

Peter