Windows 8 Storage Spaces: a how-to guide
Storage Spaces is a new feature in Windows 8 (and its server counterpart, Windows Server 2012) that could change the way you save and access files. The technology lets you combine the storage capacity of multiple disks into storage “pools”, then carve them up however you like to create any number of bespoke virtual disks. To be precise, it’s these virtual disks that Microsoft refers to as storage spaces.
What storage spaces aren’t
If you’ve ever used the (now discontinued) Windows Home Server operating system, this talk of storage pools will be familiar to you. Home Server included a unique feature called Drive Extender that allowed you to save your personal files and backups to a virtual volume that could, in reality, be spread across several physical disks. The storage capacity of your home server appliance could be dynamically expanded by hooking up any sort of internal or external drive and adding it to the pool.
Click here for our step-by-step guide to creating your first storage space in Windows 8
Broadly speaking, this is how Storage Spaces works too; but the two technologies are not the same. Storage Spaces is considerably more powerful than Drive Extender; and, crucially, Drive Extender volumes aren’t compatible with Windows 8. If you have an existing Drive Extender pool and you want to migrate it into the new OS, you’ll have to copy the files off individually within Home Server.
Another point worth making is that storage spaces are not RAID volumes. To be sure, they work on similar principles: the idea of pooling multiple physical disks into one virtual volume is the foundation of RAID, and as we’ll discuss below, storage spaces can use RAID-style mirroring and parity techniques to keep your data safe.
However, the system is designed to be more flexible and easier to administer, and trying to think of a storage space in terms of conventional RAID levels and concepts is likely to lead you astray. Announcing the arrival of the technology on the Building Windows 8 blog, Steven Sinofsky (then head of Windows development) confirmed in no uncertain terms: “the RAID nomenclature is not used.”
If you want to take advantage of Storage Spaces, you must first create at least one pool of disks to house your virtual drive. We show you how to do this (and how to set up your first storage space) in this walkthrough.
The number of disks you use in your pool is up to you. Officially a pool can support an unlimited number of drives, so the upper limit is governed only your hardware; Microsoft says the technology has been successfully tested with “hundreds of drives”.
Equally, it’s possible to create a pool containing only a single disk. This might seem pointless, but it allows you to create a storage space that can be easily expanded by adding a second drive to the pool at a later date.
However, there is a big benefit to using multiple drives, as this lets you take advantage of the various storage space resiliency options, which we’ll discuss below. Using more than one disk may also improve performance, as it allows Windows 8 to read and write data from multiple drives at once. Don’t expect super-fast file transfers, though, for reasons we’ll explore later.
Be aware that when you add a disk to a pool it’s completely wiped and becomes inaccessible to Windows. You can’t access it through the Explorer, nor save regular files onto it directly; and if you ever remove it from the pool it will need to be reformatted before you can reuse it. You can’t add only specified partitions to a pool, either: it’s the whole disk or nothing.