I'm building an UnRaid system on a Dell T440, with an array of 5 12G LFF drives for 48G total bulk storage, and two Nvme drives of 512GB each.

Unraid will host a Windows VM and a Linux VM. 

I was initially thinking one SSD would be dedicated as the boot drive for the Windows VM, and the other for the Linux VM.

 

As I read the manual, I'm now thinking that the nvme should be used as cache - "Virtual machines will perform best when their primary vDisk is stored on a cache-only share"   and "By default, Unraid will create two user shares for use with virtualization on Unraid. One share to store your installation media files (ISOs) and another to store your virtual machines themselves (domains). If you don't already have a share you use for backups, you might consider adding one as well to use for backing up your virtual machines."

 

So UnRaid will create two shares for each VM. The primary vDisk should be configured as cache-only, which will force them to reside on the SSDs which are defined as cache. But the SSDs won't benefit from parity protection (although less likely to fail, still possible). So I will also create another share in the main LFF array and use it to back up the VM primary disks.

 

Correct?

 

7 hours ago, timg11 said:

So UnRaid will create two shares for each VM.

It will create two shares for all VMs, typically the vdisks are all inside the domains share, though you can choose a custom path for each one.

 

The pool can be a mirror, so it will still have redundancy.

I have read the section on Storage Management.

I'm still not clear on how I would set up two SSD nvme drives as a mirrored cache / pool. ( cache = pool? or not?)

 

Once mirrored the two SSDs act as one drive. How do I partition that as as primary drives for Windows and Linux VMs?

Is there any further documentation on that?

 

 

https://docs.unraid.net/unraid-os/manual/storage-management/#pool-modes

 

That only covers btrfs, zfs is another way but docs aren't up for that yet.

 

You can have multiple pools, and each can have multiple disks. And you can name them and use them however you want. 'cache' was the original "pool" outside the array, but you don't have to name any of your pools 'cache', and you can use any pool for 'caching' a user share, each user share has settings for how it used pools and array and moving files between them.

 

You don't partition the drives for your VMs, you create vDisks in the domains share, and the domains share should be on a pool for performance.