Storage Spaces works only with Intel x86/x64 versions of Windows 8, not with ARM-based Windows RT systems.
NTFS and other filesystems have their
advantages, but the reliability of any filesystem is ultimately tied to
the weakest link in the chain, the underlying storage hardware. It’s a
simple fact of life that hard drives (and related storage devices)
fail, and that when they do so, they often bring your data down with
Windows has used various technologies over the
years to help overcome the inevitability of data loss. For example,
Windows 7 includes a feature called Previous Versions that
automatically stores document revisions so that you can later go back
and resuscitate an older document version when needed. It also includes
a Windows Backup utility that does a decent job of backing up important
files, or even the entire PC.
These and other recovery solutions are reactive,
meaning they provide help in the event of a worst-case scenario, be it
the accidental deletion of a file, the overwriting of a file with an
older, less correct version, or whatever. But they don’t solve the
underlying problem of relying on a single hard disk (or other device).
They don’t, for example, replicate your critical data across two or
more disks automatically so that if one drive fails, your data is still
Storage Spaces is conceptually related to
a technology called Drive Extender, which debuted in a product called
Windows Home Server. That said, Storage Spaces is the superior solution
and is technically unrelated to Drive Extender.
Windows 8 includes such a feature. It’s called
Storage Spaces, and it works with both NTFS- and ReFS-formatted disks,
providing a safe, secure, and redundant way for you to provision,
manage, and use storage that spans multiple disks, replicating your
Storage Spaces provides two basic services:
- Data redundancy:
Storage Spaces utilizes data mirroring technology to ensure that there
are at least two copies of data, each of which lives on a different
disk, to help prevent data loss in the event of a hard disk failure.
Storage Spaces lets you configure up to three disks for redundancy
purposes. (It also supports a parity feature, which provides you with
two different copies of your data but requires three physical disks;
the third disk is used for parity purposes.)
- Single pool of storage:
You can organize the storage on your various hard disks in one or more
storage pools that are managed as a single entity—called a storage pool, or simply pool—despite
having storage that could span many disks. And unlike complex
technologies such as RAID, these disks can be of multiple different
sizes and types, and can include fixed disks (SATA) and external
storage (like USB). You’re free to mix and match as you like, and
adding storage to a storage pool is as simple as plugging in a new disk
and adding it to that pool using a very simple interface.
Storage Spaces is easy to set up and configure,
and once you do that, you can pretty much just get on with life and not
worry about it anymore. Storage Spaces also integrates with File
Explorer, much like libraries do. This means you get a normal view of
the storage from Explorer, and it uses a normal, widely understood
drive letter, appearing to look and work just like a simple hard drive.
This is useful for users, but also for the OS and any applications,
since they’ll expect such things. This means the compatibility of
Storage Spaces is excellent.
Storage Spaces also lets you create a space that
is bigger than the total amount of physical storage. This feature,
which is called thin provisioning,
lets you preconfigure a space to a large size and then add physical
storage later, when it’s actually needed. Likewise, physical storage is
only allocated as it’s needed. (You’ll be prompted when needed through
Action Center, which uses a Windows Troubleshooting notification.)
Finally, in addition to working with normal
NTFS-based disks, Storage Spaces is also compatible with ReFS-based
disks. This means that today on Windows Server 2012, you can optionally
mix and match NTFS and Resilient File System (ReFS)-based disks. And in
the future, you’ll be able to do so on Windows as well.
As is always the case with new technology,
Storage Spaces brings with it some new terminology. Where a storage
pool can consist of the storage on one or more disks—though of course
you’d need two or more for redundancy—you access this storage via a new
entity called a storage space, or space.
To understand what this means, consider how libraries work in Windows 7
and 8. In these operating systems, you have physical folders such as My
Pictures and Public Pictures, and the combined, virtual view of these
folders is called the Pictures library. Spaces work the same way. You
may combine your E: and F: drives into a single pool of storage. But
you will access that pool through the filesystem using a virtual view
called a space, and that space will be given a name. In this case, it
could be called the Pictures space.
So storage spaces have names and drive letters.
But they also have an assigned resiliency type. This determines how (or
whether) the data stored in the space is synced automatically across
two or more disks, or what is called redundancy. The available
resiliency types include:
- None: In
this configuration, the space works exactly like a normal hard drive.
Data is not mirrored on two or more disks but is instead stored on just
a single disk. This configuration requires a storage pool with at least
one physical disk.
- Two-way mirror: Here,
your data is mirrored on two physical hard disks, protecting that data
from a single hard disk failure. This configuration requires a storage
pool with at least two physical disks. However, the available storage
in the pool will be halved, assuming both disks are the same size.
- Three-way mirror: In
this configuration, your data is mirrored on three physical hard disks,
protecting that data from the failure of two hard disks. This
configuration requires a storage pool with three physical disks.
However, the available storage in the pool will be one-third the total,
assuming all three disks are the same size.
A parity configuration is notably good for storing very large files, like videos.
In this advanced configuration, your data is mirrored alongside
additional parity information that could help Windows recover data in
the event of a hard drive failure.
Because spaces have this unique capability to
reserve more storage than is physically available in the attached
disk(s), the feature lets you plan for the future by pretending that
you have more storage than you do. If the data stored in the space
begins exceeding your physical capacity, you’ll be notified to add more
Meanwhile, because Storage Spaces uses thin
provisioning to allocate only a small amount of physical storage when a
new space is created, even if you create a space of multiple terabytes,
only 1 GB of space is actually taken right away.
Getting Ready for Storage Spaces
The Windows system and boot partitions, which are typically both the C: drive, cannot participate in Storage Spaces.
To use Storage Spaces, you will need at least one additional hard disk or similar storage device. It can be an external device (typically USB-based) or internal (SATA, perhaps).
But if you want to take advantage of Storage Spaces’ redundancy
features, you will need two or more hard disks. These can be different
sizes and types, and any mix of internal and external devices. Storage
Spaces is very flexible.
When you attach a new hard disk to your PC, it
will usually show up in File Explorer accompanied by a new drive
You can also display this handy menu by typing Winkey + X.
Of course, things aren’t always this simple. Most
PCs need to be shut down before internal hard disks can be installed,
and sometimes when you add an internal or external storage device, it
simply doesn’t show up in Explorer. If this is the case, you must use
the Disk Management tool to format or otherwise enable the disk. The
quickest way to run Disk Management is to mouse into the lower-left
corner of the screen, from either the Start screen or the Windows
desktop, right-click to display the new Windows 8 power user menu shown in Figure 1, and select Disk Management.
Figure 1: A new power user menu provides quick access to useful but infrequently needed tools.
Disk Management, shown in Figure 2,
shows the various physical disks that are connected to your PC and
graphically displays how each is partitioned. For example, Disk 0 in
this PC was partitioned by Windows Setup into a system reserved
partition, which doesn’t get a drive letter and second, larger boot and
system partition that’s been assigned to drive C:.
Figure 2: Disk Management
Disk Management has been around since the
earliest days of NT, so we won’t belabor its use here, but the
important thing to note is that this is the first place you should look
when you add a hard disk to your PC and it doesn’t show up in Explorer.
From this interface, you can do such things as format a disk, activate
a disk, assign a drive letter, partition a physical disk into separate
logical disks, and shrink and expand existing partitions. If it relates
to storage, Disk Management is the place to start.