VSAN Free - Hyper-V - physical storage access

[thomas_lt]

Hi,

We'd like to test VSAN Free on 2 lab servers (Win 2022 - Hyper V) running on desktop PCs fitted with 3 NVMe ssd each.
I understand using CVM is strongly recommended for performance reasons but I have some questions regarding physical storage access :
1/ As the CVM is running as a Hyper-V VM, the documentation explains we have to use DDA in order to provision the physical storage, which will work for hardware RAID controllers (ie Dell PERC controller), but will it work with a classic NVMe SSD drive on a standard PC ?
2/ In the VM settings, it is also possible to attach a physical drive to the VM, instead of a virtual disk. May we use this instead of DDA ?
3/ If 1 and 2 do not work, I suppose we'll have to fall back to the Windows application installed on the Hyper-V, but in that case should we prepare to performance issues ?

Thanks !

[yaroslav (staff)]

If it is a temporary environment, get the Trial license. Reach out to support@starwind.com. Use this thread and 1173351 as your references.

will it work with a classic NVMe SSD drive on a standard PC ?

Yes.
1. Go to device manager and disable each NVMe drive.

2. Open each device properties and NOTE Location paths Property from Details tab, that starts from PCIROOT…:

3, Open PowerShell and set variables for each location path device. See example below:
$locationpath1 = "PCIROOT(3A)#PCI(0000)#PCI(0000)#PCI(0500)#PCI(0000)"
$locationpath2 = "PCIROOT(17)#PCI(0000)#PCI(0000)"

4. Dismount each device from the host by using the Dismount-VmHostAssignableDevice cmdlet.
Dismount-VmHostAssignableDevice -LocationPath $locationPath1 -Force –Verbose

Device should disappear in Device manager.

5.Attach an assignable device to VSA VM (SW-HCA-VSA-NN) Add by using Add-VMAssignableDevice like this:

Add-VMAssignableDevice -LocationPath $Locationpath1 -VMName SW-HCA-VM-01

In the VM settings, it is also possible to attach a physical drive to the VM, instead of a virtual disk. May we use this instead of DDA

Yes, but performance will be lower. Considerably lower due to SCSI limitation.

3/ If 1 and 2 do not work, I suppose we'll have to fall back to the Windows application installed on the Hyper-V, but in that case should we prepare to performance issues ?

Yes. But if you want to RAID the disks somehow, you need to use StorageSpaces then. It may eat quite some of the performance.

[thomas_lt]

Thank you for help !
Regarding Replication and Data NIC speeds, is 10GB more than recommended for a 2 nodes cluster ? Or 1GB will do the job, with a very small performance decrease ?

[yaroslav (staff)]

You are always welcome. It all depends on the performance expectations and the underlying storage you have.
For NVMe-based systems, the performance will hit the glass ceiling of iSCSI anyway (can be compared to RAID 5 out of SSDs' performance). 1 GBE will absolutely kill the performance of this setup. For a small lab though, where you do not aim to set HCI performance high scores, 1 GBE should do it.
Yet, it is absolutely not enough to enable the whole NVMe potential.