A week ago, the latest post to the Windows 8 blog was entitled “Virtualizing storage for scale, resiliency, and efficiency.” And while the whole thing is definitely worth perusing, I want to zoom in on something that catches my particular fancy in this blog (it also caught Word and Windows guru Woody Leonhard’s attention in the latest Windows Secrets newsletter, too, which is what initially brought it to my attention; his piece is called “Storage Spaces might be Win8′s best feature yet“).
But first, I have to explain why I think the Storage Spaces feature is so awesome, by hearkening back to another hobby horse of mine — namely, Windows Home Server, aka WHS (I’ve blogged five times on this platform right here: once in 2008, and twice each in 2009 [1,2] and 2011 [1,2]). Turns out that Windows Server used to support a feature called Drive Extender that essentially allowed you to shrink or grow a multiple-disk logical volume simply by adding or removing space, then doing likewise with hard disks, on the system. No need for migration, recopying, partition re-sizing, Disk Management, and so forth: just a few commands to tell the file system what’s going on, and smooth sailing throughout.
I was incredibly bummed when it became clear that WHS 2011 (the latest and greatest version, out last year) did not continue earlier versions’ support for this feature, and thought perhaps we might never see its like again in the Windows World. I was wrong! In Windows 8, Storage Spaces lets users set up logical volumes that are bigger than the combined disk space provided for them, so you can grow the physical space over time to match the logical definition (Microsoft calls this “thin provisioning”). Here’s how Rajeev Naga, a group manager for Microsoft’s Windows 8 Storage and File System team explains what Storage Spaces can do:
Organization of physical disks into storage pools, which can be easily expanded by simply adding disks. These disks can be connected either through USB, SATA (Serial ATA), or SAS (Serial Attached SCSI). A storage pool can be composed of heterogeneous physical disks – different sized physical disks accessible via different storage interconnects.
Usage of virtual disks (also known as spaces), which behave just like physical disks for all purposes. However, spaces also have powerful new capabilities associated with them such as thin provisioning (more about that later), as well as resiliency to failures of underlying physical media.
And if and when you exceed the original maximum allocation for this storage pool, Storage Spaces simply notifies you in a pop-up window that you need to add more capacity, which you can do by plugging in more disks, then allocating them to that pool. Even cooler, pools can be designated as mirrored so that there will always be at least two (possibly three) copies of data on different physical disks within that pool. And should any disk fail, Storage Spaces automatically regens data copies for all affected holdings as long as enough alternate physical disks remain available within that pool. It’s not RAID, but it is fault-tolerant and resilient, and a great technology for all kinds of SOHO and end-user applications. The parity designation also permits data to be reconstructed in the face of physical disk failures. They work best for big, relatively static files (like music, movies, home videos, and so forth) which are sequential in nature and require little or no updates to existing files.
Here’s how to work with Storage Spaces. You can use Windows PowerShell commands to create a storage pool, and to set up Storage Spaces that reside in that pool, or you can use the Storage Spaces item in Control Panel, to go through that process. This means selecting drives, then naming a storage space, assigning a drive letter, establishing the layout (default, mirrored, or parity), and assigning a maximum size. Afterward, you can always add more drives as needed, or make changes to configuration data likewise. Right now, the Win8 Developer Preview only supports storage spaces up to 2 TB in size, but when the Win8 Beta ships in February (next month, that is) you’ll be able to create storage spaces of arbitrary size.
What a great feature to bring to the Windows desktop. This may indeed be a true “killer feature” that prompts users to to upgrade to the new OS to exploit its capabilities, particularly those with big media collections!