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Dell Storage with Microsoft Storage Spaces Best Practices Guide

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Enclosure awareness

Enclosure awareness provides fault-tolerance for an entire enclosure failure, by ensuring that data copies are spread across the available enclosures, such that the loss of an entire enclosure still allows access to the data. Enclosure awareness requires at least three storage enclosures.

Table 1. Enclosure configurations for failure coverage
Resiliency level	Storage enclosure failure coverage
	Two storage enclosures	Three storage enclosures	Four storage enclosures
two-way mirror	1 disk	1 enclosure	1 enclosure
three-way mirror	2 disks	1 enclosure + 1 disk	1 enclosure + 1 disk
Parity	1 disk	1 disk	1 disk
Dual parity	2 disks	2 disks	1 enclosure + 1 disk

Enclosure awareness is configured when you create a VD.

Run the following PowerShell command for enabling enclosure awareness.

New-VirtualDisk -FriendlyName <vdName> -StoragePoolFriendlyName <poolName> 
                                    -IsEnclosureAware <$true|$false> -ProvisioningType Fixed 
                                    -ResiliencySettingName<Simple| Mirror| Parity> -PhysicalDiskRedundancy <1|2> 
                                    -StorageTiers<ssdTierObject, hddTierObject> -StorageTierSizes <ssdTierSize , hddTierSize>

For example, a new VD is created with the name exampleVD3 in storage pool MyPool1. This VD uses enclosure awareness so the IsEnclosureAware attribute is set to $true.

New-VirtualDisk -FriendlyName exampleVD3 -StoragePoolFriendlyName MyPool1 
                                    -IsEnclosureAware $true  -ProvisioningType Fixed -ResiliencySettingName Mirror 
                                    -PhysicalDiskRedundancy 1 -StorageTiers $ssd_tier, $hdd_tier 
                                    -StorageTierSizes20GB, 10TB