Storage for MS Hyper-V VM's

[GraKez]

Hi,

Firstly, if I ask a question that is already well documented, I am sorry, and please tell me to go look there.
There seems to be a lot of information about VMware, but not much on MS Hyper-V (which is where our servers are at the moment)

And whenever I mention Hyper-V in my search, I get a heap about trying to virtualize FreeNAS, which I do NOT want to do.

I want to connect our MS Hyper-V systems to FreeNAS to open up two options a) data snapshots and b) replication to a 2nd FreeNAS box.

These are business systems so I will be using:
1. ECC RAM,
2. mirrored SLOG
3. will have sync=always
4. Unsure if I will use RaidZ2 or Striped Mirrors yet
5. May have to go to 10Gb NICs

What I am unsure about is how I will make the FreeNAS storage visible to the Hyper-V machines.
My knee jerk reaction was to use iSCSI, but I could also use SMB, and with my Centos OS maybe use NFS

Main objective:
At the moment the servers are virtualized (MS Windows Server & Centos) but they are each locked into a specific box with direct storage on Intel RAID Controllers in the same box.
Daily backups get pushed off site, but a restore could be a long process, this is why I would like to keep the current backup process, but also have snapshots and replication via FreeNAS.

My main focus will be on the Centos machine which runs a small (but important) MySQL Database, and also has 5Tb of data files.
So
I could link via iSCSI to the Hyper-V host and make the drive look locally mounted to the Centos VM
or
I could link via iSCSI directly to the Centos VM (but I read the iSCSI would run better off the host)
or
I could skip iSCSI and have the Centos VM map up to an NFS share on FreeNAS

Any advice on which way I should focus would be very much appreciated.

 

[jgreco]

I seem to recall that there was some issue with MS Hyper-V wanting certain iSCSI features that FreeNAS lacked, but I think that was before the kernel iSCSI was introduced. I'm not sure of the status of all that right now.

You can absolutely use iSCSI or NFS directly from a guest on the hypervisor. However, if you can stick with NFS and file-based storage, that can be a win sometimes. See https://forums.freenas.org/index.ph...res-more-resources-for-the-same-result.28178/

 

[GraKez]

Apparently the guest VM cannot enjoy all of the hardware feature offered to the host (iSCSI) but you cannot believe everything that you read.

 

[jgreco]

No, the problem was something to do with CSV and locking, IIRC.

 

[cyberjock]

From my experience with TrueNAS support, CIFS/SMB is the tried-and-true way to go for Hyper-V. It "just works" properly with Hyper-V. Very few people use Hyper-V, but all agree that CIFS was the way to go. I don't remember if there was something stopping them from using something else, if they thought CIFS was easier, or if there was a performance reason.

 

[Nick Howard]

I've got a 4TB iSCSI file extent to my Hyper-v host and currently have 3 VHDX VM's on there. I've experienced no issue's doing this although I'm unsure if it's recommended.

 

[Mlovelace]

Hyper-V (shudder)... SMB (CIFS) is the preferred storage method, however freeNAS does not have the multi-threaded version of samba (yet), so you would be better off using iSCSI with MPIO on the host.