Adding a large volume to a VM in a Hyper-V failover cluster

Question

Hi all,

We have three Windows Server 2019 machines in a Failover Cluster.
There is a Dell SC storage connected to these servers.

Currently, we create the volume on the SC storage, map it to the Cluster, and add it into the Failover Cluster using CSV.

We then create vhdx images on the CSV and add them to the VMs as needed.

However, we have one system that needs a lot of storage (30+TB). This is hosting large medical image files, and has high IO access to them.
This had previously been set up by mapping multiple 2TB vhdx to the VM and creating a Spanned volume within the VM.
We had done this as we found that creating a VHDX over 2TB starts creating exponentially worse performance the larger the VHDX becomes. The Spanned volume removed that performance issue.

I was wondering what the best method to add a large 40TB volume to this server would be?
Should I continue with the multiple 2TB VHDX files and span them within the guest OS or is there a better option?

Further information is that we use Veeam to backup our VMs, in case that impacts things.

I have most likely forgotten relevant information, so please let me know if there is more information needed.

Answer 1

Hi AnthonyGreen,

My advice is as follows:
You can create striped volumes in place of spanned volumes for the following reasons:
(1) Spanned volumes are similar to simple volumes, which are first filled with the space allocated for the volume on one disk, and then start from the next disk, and then fill the space allocated for the volume on the disk, which is actually a union of simple volumes.
(2) A striped volume is composed of two or more fast hard disks, and must be built on a dynamic disk like a spanned volume. In addition, striped volumes use RAID-0 to distribute data across multiple disks, and striped volumes perform best across all Windows disk management policies, while improving I/O performance by allocating I/O requests across multiple disks (which is what you need). The disadvantage of striped volumes is that they cannot be scaled and mirrored, and they do not provide fault tolerance.
(3) Other volumes similar to ordinary volumes, mirrored volumes (storage cost is relatively high, not recommended) and RAID-5 volumes are not recommended.
Here's how to create a striped volume:
(1) Open Disk Manager and select Create Volume;
(2) Select "Stripe Volume" and continue to click "Next";
(3) Select the disk you want to use and the size of the space, click "Next", and complete the creation according to the on-screen prompts.
Hope my answer helps you!

Best Regards,
Xu Gu

Answer 2

Thanks for the reply Xu Gu.

Just to clarify that the best option for my scenario is still to create multiple 2TB VHDX files and combine them into a single volume within the attached VM?
I just have to decide which option I prefer - striped or spanned?

Kind Regards,
Anthony

Answer 3

Thanks for the response. I was waiting to see if there were any comments about a single-volume option.
But it seems that the multiple 2TB VHDX files either in Striped or Spanned configuration are the recommended options.
My concern on the Striped is the comment on the lack of scaling.
We will need to increase space every 3-6 months, so might not work too well.