WHS 2011: Living without DriveExtender

With the announcement from Microsoft that DriveExtender support has been dropped from Windows Home Server 2011, I've been on the lookout for other solutions for when my aging HP MediaSmart finally needs replacing.

Should I stick to Windows Home Server?

I believe that for me, the answer is "Yes". Windows Home Server still has a number of features that, in my opinion, make it a better solution than a simple NAS box or Linux based alternative. The most critical of these is the automatic backup integration with Windows based systems, for the following reasons:

  • Computers can be set to automatically wake-up, backup to the Home Server and then power down again. It's a very successful fire-and-forget solution.
  • If an identical file blocks exists on many computers, then the Home Server only ever stores one version of the block in the backup area. This drastically reduces the amount of storage space needed to store backups, and also ensures that backups can be done quickly, even over a WiFi connection.
  • Bare-Metal restores; Backups can be restored to a computer by booting from a restore CD - there is no need to install a base operating system onto the system first.

In addition, I like the ability to install services and "standard" windows applications on the server to run in the background. Although Linux solutions also allow this, the installation and configuration of such services tends to be a lot more complex.

Lastly, the Windows Home Server requires very little maintenance and can be operated by users with limited technical knowledge.

DriveExtender - What is it?

The first version of Windows Home Server had a feature called DriveExtender (DE) that managed the disks attached to the Server and presented them to the user as a single large Drive. This wasn't a simple concatenation of the disks (a JBOD configuration) nor was it a RAID solution. It was superior to both for the following reasons:

  • The user could specify which top-level folders (shares) contained important data that needed to be protected. DE would then ensure that a minimum of two copies of the important data were kept, and that the copies would belocated on different disks in case of failure.Note: Unlike RAID mirroring, where an entire disk or group of disks are mirrored, DriveExtender allows more granular control of which files would be duplicated, and therefore resulted in much less wasted disk space.
  • DriveExtender allows disks of any size to be added to, or removed from the storage pool thereby allowing the total capacity of the pool to be changed with ease. Additional space could be added quickly and simply, and the removal of a disk from the storage pool would distribute the files from the disk being removed to the other disks (maintaining multiple copies on different disks where necessary) as described above.Note: RAID is used by other NAS and Linux devices to achieve a similar effect in increasing the storage available, but with a number of limitations: drives must be of the same size/capacity, and the time taken to re-stripe data increases with the size of the storage pool (it is typical for a re-stripe operation to take anywhere from a few hours to a few days).
  • Finally, DriveExtender writes all files to the disks in the storage pool to standard NTFS filesystems which can be read by any Windows computer (and even Linux distributions!). In the event that the Home Server suffers a hardware failure, the disks can be connected to another computer and read without any additional software/hardware.

In my opinion, if you use a hardware RAID controller to manage your storage, then you need to be backing up your data regularly. In the event that your RAID controller dies, you won't be able to read any of the data on the disks. And you just know how long the odds are on  getting a replacement with the exact same chipset and firmware version two years down the line are going to be...

What has Microsoft replaced it with?


Microsoft have decided that DriveExtender does not offer the high performance needed for business users (despite the fact that this is Windows Home Server), and argue that the availability of 1Tb and 2Tb drives make this a non-issue (for your information Microsoft, I already have 5Tb in my Home Server, and an empty drive enclosure where I can add another 4 drives!).

With Windows Home Server 2011 it will be up to us, the users, to manage drive letters and implement some kind of mirroring for important data, or to configure RAID on the server (despite the manay advantages DE had over RAID).

Hope for the future!

Currently in development, and scheduled for release in June 2011 is a product by Division-M called Drive Bender. This is intended to offer all the features of DriveExtender, including the creating and management of a central Storage Pool which can be shrunk and extended at will, and with the option to duplicate selected folders for added protection. Division-M plan to offer the product as a plugin for Windows Home Server 2011, but crucially, they also plan to offer it for other Windows platforms, including Windows XP, Windows 7 and Server 2008!

It looks like the market for software to replace DriveExtender is hotting up... other products have been brought to my attention such as DrivePool and DataCore. The future looks bright for WHS2011 !