Western Digital are leading the charge to implement a new “Advanced Format” technology in their Caviar Green 1TB, 1.5TB, and 2TB hard drives. This new technology is replacing the traditional 512 byte hard drive sector with a 4 kilobyte (4,096B) hard drive sector to improve future drive efficiency and capacity. The move to 4KB sectors is likely to be adopted by all manufacturers in 2010-11.

“So what?”, you may ask, and it’s a fair question. Right now, there’s little consumer benefit to the transition, other than in the future, it will enable drives larger than 2TB to be developed. (There’s a great explanation of the detail around the technology here). The issue is that only Windows 6.x operating systems and above (that’s Vista, Windows Server 2008, Windows 7 and Windows Server 2008 R2) have in-box support for the new technology, whilst older operating systems which aren’t aware of the tech are likely to have poor default performance from these drives due to alignment issues.

So, Western Digital have released a utility to enable these drives to be realigned for use on older operating systems such as Windows XP and Windows Server 2003. A jumper solution is also available as a work around. But guess what? The utility, called WD Align, is blocked from running on Windows Home Server. Great work Western Digital!

WGS Forum members are starting to hit the issue, and are seeking alternative ways of working around the problem – with some, (but not total) success. Nailing compatibility is likely to require WD or Microsoft patching the utility or operating system for compatibility, but with a new version of Windows Home Server in development, who knows if that is likely?

There is a great thread going over on the forums which explores the issue in detail:

WD Green 2Tb Drives – Should We Use WD Align?

A couple of readers have hacked the WD Align file to remove the OS check, whilst this appears to enable alignment support for new system drive installations, but problems are still occurring for drives attached to the storage pool. You can spot the new Western Digital drives by their model number, which will end in EARS.

Reader Headhunter3000 states,

  • EARS as system drive must not be jumpered but aligned immediately after install (before other EARS drives are attached as data pool drives).
  • EARS drives as data pool drives can only be used with jumpers
  • Never run WDALIGN on WHS with a jumpered EARS drive as data pool drive.

For now, your safest bet is to avoid the new Western Digital Advanced Format drives with Windows Home Server until a full resolution can be found. With WHS v2 being based on Windows Server 2008 R2, it should not be affected by this problem

Update: I pinged the Windows Home Server team and they’ve confirmed they’re aware of the drives and are in discussion with Western Digital. That doesn’t necessarily mean a fix is on the way, but keep your fingers crossed.

More Info: WGS Forums