Windows 8's new Storage Spaces functionality will easily allow users and system administrators to pool different physical drives together into one logical drive, writes Rajeev Nagar on the Building Windows 8 blog. This functionality, which is similar in some ways to the now-discontinued Windows Home Server Drive Extender, will allow drives of any capacity connected to a PC by USB, SATA, or SAS interfaces to be seen by the OS as one large drive.

Once you've created a storage pool using two or more drives, you can then set up one or more "spaces" that will be seen by the operating system as a logical drive which can be formatted, partitioned, and used just as a physical disk would be. To provide redundancy, you can either apply the "mirrored" attribute to your pool, which makes sure that a copy of every file in the pool is stored on at least two different physical drives, or the "parity" attribute, which uses some drive space to store redundancy information - in the event of drive failure, this information is used to rebuild your pool and enforce mirroring. Microsoft notes that while the two redundancy options are similar, the "parity" attribute is best used for large sequential files or less-frequently-accessed content, since it has a higher random I/O overhead. 


When creating a new Storage Space, you can specify a maximum size larger than the amount of available physical space - the system will prompt you when the storage pool needs more drives to work with. Microsoft calls this "thin provisioning," which means that drive capacity is only reserved as you store data to the drive rather than all at once. You can also expand the maximum size of the Storage Space at a later point if necessary. Creation of these spaces can be scripted using PowerShell.

For an in-depth look at how this technology works (and a FAQ which answers, among other questions, some inquiries about its similarities to and advantages over RAID), check out the full post using the link below.

Source: Building Windows 8 Blog

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  • hechacker1 - Friday, January 6, 2012 - link

    Considering that checksumming is left to applications to perform on the files, and that an API exists to call up different copies of the same file in the Storage Pool, I'd bet that Microsoft has another application layer on top of it that actually get the correct copy.

    If they don't provide something, it doesn't sound to hard to use the API to checksum the entire pool, and then periodically rescan for any changes. I'm guessing third party disk backup software could easily hook into this. I'm awaiting to see what MS does have planned, because that sounds like a easy to make program assuming their API is useful.
  • Wardrop - Friday, January 6, 2012 - link

    This is one welcome step closer to what I see as the inevitable future, which is data-redundancy built into the OS, and enabled by default. When you think about it, it's a little crazy that in 2012, backup is still something that the user must explicitly setup. Having data redundancy should be the default. On a new computer or fresh installation of Windows, backup schedules and procedures should already be in-place. It should be a required screen on the Windows installation wizard. All new computers should come with data redundancy already enabled and active. Anyone who's not a guru, probably does not have an adequate backup scheme, and anyone less than a power-user probably doesn't have a backup scheme at all. The least we could do is get the data of those non-power-users backed up, and provide better guidance from within the OS to help those power-user's who may not have the best backup scheme (e.g. backing up to another internal hard-drive, where a power supply failure or a malicious software attack could easily destroy everything).

    Given the cost of storage relative to how much data the average user actually has, it's crazy that we're not already making better use of the abundance of storage available. Windows Volume Shadow Copy (aka. Preview Versions) was thankfully brought to the home edition of Windows 7 (Windows Vista only had it in Business or Ultimate), but it still needs some improvements. "Previous Versions" doesn't easily allow you to increase the frequency of snapshots. Adjusting the schedule in the Windows 7 task schedular can often break it. I've personally had to resort to a VBscript that forces a snapshot, but doing so causes the machine to hiccup for about 5 seconds at the start of the process; not very nice when you're playing loud music. If I've got a 3TB drive and I'm only using 1TB, I want the remaining 2TB of free space to be previous versions, which are deleted only to make room for more data or newer snapshots, like how Windows caches regularly used resources in memory, as like RAM, free hard-drive space is useless if it's not being used.
  • hechacker1 - Friday, January 6, 2012 - link

    I agree. But I think MS needs to take a step forward and change NTFS to be able to specify redundant copies for all files (assuming free space). ZFS allows you to specify how many copies you want of each file (at the block level), and it can do that with a single drive.

    Even having a single backup copy around could save a lot of people's data when one part of the disk corrupts. Often it's just a critical boot file or registry that gets wiped and suddenly it doesn't boot.

    MS could save everybody a lot of effort if they just implemented this already.
  • Wardrop - Friday, January 6, 2012 - link

    Yeah, the file system is one of those fundamental areas of an operating system. Even a small improvement to the underlying file system can bubble up and positively affect a users entire workflow. I'm surprised it's not has even more attention from the Windows team.
  • Jeff7181 - Saturday, January 7, 2012 - link

    It's kinda cool though that it's sorta like software RAID that can be changed on the fly from striping to mirroring to striping with parity to a mirrored striped with parity. Though I'm not sure this is all that useful for 99% of people. I'd much rather see Windows support an SSD as a cache for a larger mechanical HDD.
  • B3an - Saturday, January 7, 2012 - link

    You have a small imagination.

    Killer feature for all servers, HTPC's, video editing, or ANYONE who actually does any work or has important data on there PC. Improved speed and complete data backup without having to do anything, not to mention very easy to setup?! I'm sure OEM's will ship some PC's will this enabled by default.
  • Touche - Saturday, January 7, 2012 - link

    RAID and this are NOT backup!
  • landerf - Saturday, January 7, 2012 - link

    Can we finally drag and drop between internal drives without using special key combinations? Seems like a real obvious thing but there's no way to set that behavior in 7.
  • Wardrop - Saturday, January 7, 2012 - link

    You can drag and drop between drives. It copies the dragged files to the destination folder, which is a much more desirable default than moving the files (cut-paste). The reason being is that imagine if a user dragged a file from an internal drive, to a mates external drive. If he assumed the drive copied the data, but it actually moved it (deleted it from his internal drive), then he's essentially unknowingly deleted his data. If however someone drags and drops to an external drive, if they expected the files to be moved, but they were copied, no data has been lost. It's merely left files somewhere.

    Now, I know you're talking about internal-to-internal, but I mentioned internal-to-external because I believe it would be a significant usability problem if the behaviour for drag and drop to an external drive different to that of an internal drive. The line can also sometimes be blurred between what is an external or internal drive. A lot of people use external drives as if they're internal, and vice versa.

    You're essentially suggesting to make the default drag-drop behaviour of Windows Explorer more dangerous, which obviously isn't going to happen. I've even be hesitant about adding the option, as users may roam between differently configured workstations, where once again, the inconsistency between drag-and-drop behaviour may cause accidental data loss.
  • SlyNine - Saturday, January 7, 2012 - link

    Anyone interested in this should look at flexraid. Snapshot raid is the best thing to happen to my media collection ever.

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