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 affects performance. Simple VDs are
not recommended, because they provide no resiliency.
Table 1. 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 | ![This image shows equation for disk space efficiency.](https://dl.dell.com/topics//dsms_bpg_pub-v2/images/GUID-C5CB8EA0-2543-4BC7-81E7-8739AD148CA3-low.png)
| 1 Disk | Example with column count of 7: 218.4 TiB raw disk space 187.2 TiB usable disk
space
|
Dual parity | ![This image shows equation for disk space efficiency.](https://dl.dell.com/topics//dsms_bpg_pub-v2/images/GUID-44AD811D-6772-40D5-8E4C-F745929D6964-low.png)
| 2 Disks | Example with column count of 7: 218.4 TiB raw disk space 124.8 TiB usable disk
space
|
- NOTE: Creating
VDs with thin provisioning is not supported.
Fixed provisioning enables 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. Spread the VDs evenly across all pools, and assign
them evenly to the 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
- NOTE: Dell recommends
that you create storage spaces no larger than 10 TB. For more information,
see the
Dell Storage with Microsoft Storage Spaces
Support Matrix
available at
Dell.com/dsmsmanuals.