Figure 4.4 Storage Spaces architecture showing a hot block moving from the HDD
tier to the SSD tier
When you use tiering, you must have a sufficient number of disks from each tier to
meet the data-resiliency options. For example, if mirroring is selected for a virtual
disk, at least two disks need to be available with enough space in the HDD tier and in
the SSD tier. The same applies for the write-back cache. Storage Spaces will not allow
a drop-in resiliency.
To utilize tiering and the write-back cache, you can use PowerShell, which gives
granular control (although by default a 1GB write-back cache is created on all new
virtual disks if sufficient SSD space and disks are available in the pool), or Server
Manager for a simpler experience but with less granularity in the configuration. In the
following PowerShell commands, I create a storage space from four physical disks,
two HDDs and two SSDs, and then create a virtual disk and create a volume:
#List all disks that can be pooled and output in table format (format-table)
Get-PhysicalDisk -CanPool $True | ft FriendlyName,OperationalStatus,Size,MediaType #Store all physical disks that can be pooled into a variable, $pd $pd = (Get-PhysicalDisk -CanPool $True | Where MediaType -NE UnSpecified) #Create a new Storage Pool using the disks in variable $pd #with a name of My Storage Pool New-StoragePool -PhysicalDisks $pd
-StorageSubSystemFriendlyName "Storage Spaces*" -FriendlyName "My Storage Pool" #View the disks in the Storage Pool just created Get-StoragePool -FriendlyName "My Storage Pool" |
Get-PhysicalDisk | Select FriendlyName, MediaType