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what format to use for new server to host VMs?

Post by AndyFearless » Sep 14, 2018 11:17 am

I think I know the answer but wish to clarify before I make a costly mistake! Always nice to get things right first time when building new systems.

My existing system has a local repository, and a remote repository that runs the VBR as well - both are physical servers with 64k REFS drives as that is what is recommended. Everything is fine and they are backing up a selection of 2k8r2 servers nightly. All good.

I'm building a new Hyper-V host on new hardware. It will run server2016 and host all new 2016 guest VMs. Ignoring the OS C drive which is NTFS, I have two 4 Disk RAID10 volumes - this is where my VMs will live. What format should I use for them? These are not repositories, but they will be backed up by Veeam [to the repositories mentioned in paragraph 1 above].

Is the current thinking still to use 64k REFS volumes? I was going ahead with this but got a little scared when I found the 80-page thread about excessive memory/cpu consumption using REFS.



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Re: what format to use for new server to host VMs?

Post by nmdange » Sep 14, 2018 2:54 pm

Microsoft recommends using 4K ReFS on volumes hosting Hyper-V VMs on Windows Server 2016. This isn't really a Veeam-specific question as Veeam can back up Hyper-V VMs regardless of the filesystem. 64K is only recommended for Veeam repositories, that doesn't apply to other types of workloads. Since the volume the VMs are on does not make extensive use of fast-clone, the issues with ReFS on Veeam repos don't really come into play.

Mike Resseler
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Re: what format to use for new server to host VMs?

Post by Mike Resseler » Sep 17, 2018 6:29 am


Nmdange is right. Microsoft clearly makes the 4K recommendation for volumes that hosts VMs. You can read why here: https://blogs.technet.microsoft.com/fil ... -and-ntfs/

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