A new feature in windows 2012 installed by default in all server editions! Microsoft calls it Storage Virtualization and the idea behind it is somewhat familiar to most administrators that have worked on a hardware RAID controller before. In fact disk virtualization is working like a software RAID with better scalability, resiliency and optimization.
The basic concept is to group physical disks together into a container called storage pools and to manage those disks as a single storage space. Afterwards, in these storage pools, you create virtual disks on which you specify a layout which is simply a raid level.
The Raid Levels of a virtual disk can be:
- Simple: This is a stripe set with no parity, similar to RAID 0. There is no redundancy. It has a better performance and more capacity available compared to a configuration with a single disk.
- Mirror: This is a mirror set, similar to RAID 1. Data is duplicated across two or three disks, increasing reliability but decreasing the total size in half. This configuration protects data from a single drive failure or from two simultaneous drive failures in the case of a five disk configuration.
- Parity: This is a striped set with distributed parity, similar to RAID 5. This configuration protects data from a single disk failure. It requires a minimum of three disks to operate.
Storage Virtualization can be configured via Windows 2012 server manager or PowerShell. To set up storage virtualization in server manager you have to navigate to File and storage services -> Volumes -> Storage Pools.
Note that the Primordial is the system’s default storage pool that includes all unallocated physical disks. To create a new storage pool you have to right click on the white-space, on the Storage pools pane, and select the new storage pool option:
Enter the name and the description of the new storage pool
Select the physical disks that will participate in the storage pool, along with their allocation type. The allocation type can be set to auto or to hot spare. Auto means that the physical disk will actively participate in the storage pool. Hot spare means that the drive will not actively participate in the storage pool. It will take over in the case of a drive failure.
The drives must be online and in unallocated state in order to appear in the wizard. The drives can be of any type including SAS, VHD, VHDX, USB etc.
Review the Confirmation dialog and press Create to create the Storage pool.
After you create a storage pool you will be able to create one or more virtual disks. To create a virtual disk right click on your storage pool name, in server manager, and select the new virtual disk option. Select the storage pool on which you wish to create the virtual disk
Type the virtual disk’s name and description
Select the storage layout
Select a provisioning type: Provisioning type can be either thin or fixed. In Thin mode the virtual disk will use the minimum required space, as needed, growing gradually up to the Vdisk size. In fixed mode the whole size will be committed from scratch.
Specify the Vdisk size
Review the confirmation dialog and create the virtual disk.
By default, after the completion of the Vdisk wizard the new volume wizard will start. It will guide you through the volume creation on the newly added Vdisk.
In case you want to add more physical drives in a provisioned storage pool, right click on that storage pool’s name and select the add physical disk option.
For your information, the operations you can perform on a Vdisk is to repair, detach, mask/unmask, extend or delete it.
To replicate the procedure by using powershell
Firstly, list the available physical disks along with their status and their ability to participate in storage pools (CanPool value). Get-PhysicalDisk:
In this example you will associate four physical disks in auto mode and one in hot spare mode. To accomplish that you have to create a variable containing the four disks you want to allocate, in auto mode, in a new storage pool.
In this example you want to include the physical disks 1-4 and not 5.
Inject that variable into the new-StoragePool cmdlet by using the –physicaldisks switch:
Add physical disk 5 as a hot spare: create a variable containing the physical disk 5 and then feed that variable into the add-physicaldisk cmdlet
Finally, to create the virtual disk, use the new-VirtualDisk cmdlet as shown below
You can check out the storage pool and the virtualdisk settings by using the get-StoragePool|FL and the get-virtualDisk|FL cmdlets respectively.
As a final step you may use either diskpart or powershell commands to create the appropriate volumes on these virtual drives.