Dell Storage with Microsoft Storage Spaces Best Practices Guide

When you configure a VD, there is an option to select from various resiliency types — simple, Two-way mirror, three-way mirror, single parity, or dual parity.

Dell recommends you to use two-way or three-way mirror VDs. Mirrored VDs are optimized and provide the best performance and resiliency for Hyper-V workloads.

Parity VDs are intended for workloads which are sequential, such as backup and archiving. Do not use parity VDs for random workloads, because this impacts performance.

Simple VDs are not recommended, because they provide no resiliency.

Table 1. Pool fault-tolerance and efficiency . Pool fault-tolerance and efficiency

Resiliency type	Disk space efficiency	Fault-tolerance for each storage pool	Example enclosures with 60 x 4 TB HDD (3.64 TiB)
Simple	100%	0 Disks	218.4 TiB raw disk space 218.4 TiB usable disk space
Two-way mirror	50%	1 Disk	218.4 TiB raw disk space 109.2 TiB usable disk space
Three-way mirror	33%	2 Disks	218.4 TiB raw disk space 72.07 TiB usable disk space
Parity		1 Disk	Example with column count of 7: 218.4 TiB raw disk space 187.2 TiB usable disk space
Dual parity		2 Disks	Example with column count of 7: 218.4 TiB raw disk space 124.8 TiB usable disk space

Fixed provisioning allows usage of storage tiers and failover clustering, neither of which are supported with thin provisioning.

Storage Space size is based on the number of disks and pools you have. You must spread the VDs evenly across all pools, and assign them evenly to the storage nodes in the cluster to allow for load balancing and resiliency.

You can run the New-VirtualDisk Powershell command for more advanced VD creation options.

For example,

A new VD called exampleVD1 was created in storage pool MyPool1. This VD was a Three-way mirror so the ResiliencySettingName attribute was set to Mirror and the PhysicalDiskRedundancy attribute was set to 2. Because storage tiers are used, the disk space sizes of the tiers are specified as part of the VD.

New-VirtualDisk -FriendlyName “exampleVD1” -StoragePoolFriendlyName “MyPool1” -ProvisioningType Fixed -ResiliencySettingName Mirror-PhysicalDiskRedundancy 2 –StorageTiers $ssd_tier, $hdd_tier –StorageTierSizes 400GB, 40TB