The state of deduplication on ReFS?

[Wixner]

Hello Veeam Community.

I'm currently building a PoC to push our VM's (Hosted on a Hyper-V Cluster using Windows Server Datacenter 1709) and a couple of our customers VM's (VMware 5.5 through VMware 6.5 and some Standalone Hyper-V Servers) to a remote ReFS Repository. In the future we have plans to offer endpoint backups using Cloud Connect and Veeam Agent for Windows/Linux. My initial design pattern is that a single backend repository won't exceed ~30TiB but instead we will add an additional 30TiB to a Scale-Out repository trying to keep backupchains on the same backend repository.

What's the current state of enabling deduplication on ReFS for Veeam Backups? Are there any official guidelines of best practices for this setup or are hardware dedupers the only viable way to keep the backups nice and tidy as well as efficiently stored?

Cheers

[marco.horstmann]

Hi Patrik,

ReFS has no deduplication function so you can only dedup within a backup file.

Kind regards
Marco

[Wixner]

As of Windows Server 1709 deduplication is available for ReFS

[marco.horstmann]

Ok that’s new for me. Actually I haven’t got any best practices.

[Wixner]

AFAIK it's the same dedup engine used on NTFS that has been made available for ReFS so i'd guess the NTFS-dedup best practices would apply on ReFS as well

[nmdange]

You can't combine fast clone and dedupe on ReFS on 1709. Personally I think fastclone is much better than dedupe, despite the issues it's had.

[Wixner]

You can't combine fast clone and dedupe on ReFS on 1709. Personally I think fastclone is much better than dedupe, despite the issues it's had.

Consider the fact that my ReFS-repository would be accessed over SMB (as 1709 is a core-installation only) would I still benefit from fastclone?

[nmdange]

You can still add server-core systems to Veeam as a Windows-based repository. And yes you would still benefit from fast-clone. My ReFS repos are 2016 Core. Though to be honest, I would lean away from using SAC for infrastructure like this since Microsoft may release fixes for ReFS on 2016 that they leave out of 1709 because the fix is in 1803 (or in the future 1809 release).

[Frenchyaz]

We have enabled rEFS with Deduplication on Windows server 2019 and everything seems okay. On a 64TB volume (maximum size supported) we get:
FreeSpace SavedSpace OptimizedFiles
--------- ---------- --------------
58.6 TB 11.24 TB 318

And we have files bigger than 1TB...

Note: We upgraded from Server 2016 1607 to Server 2019 as 1709 and 1803 are only core servers. As we wanted rEFS and Deduplication, it was a good timing. Also, VBR doesn't support Server 2019 until 9.5u4 (scheduled released January 2019) but it works.