KB2385637: Windows Home Server and Advanced Format Hard Disks

At WGS, we have seen many a forum post about the trials and tribulations with Windows Home Server and Advanced Formats drives.  Microsoft has finally released a KB article outlining when you can use an AF drive and when you cannot.

The short version:

  • Windows Home Server v1: Do not use Advanced Format disks in your Windows Home Server v1.
  • Windows Home Server ‘Vail’: Upcoming Windows Home Server codename ‘Vail’ will support Advanced Format disks as server disks.
  • Client Machines: Windows Home Server functionality is compatible with client computers using Advanced Format disk for Windows Home Server v1 and the upcoming version codename “Vail”.


This is just a thought, but I wonder if there is an effort being made here to steer people away from WHS v1 and towards a more state-of-the-art OS like WHS 2011.  What are your thoughts on this?

[box type=”info”]More: KB2385637 [/box]

Information regarding Windows Home Server and advanced format hard disks


To improve enable continuing capacity gains in hard disk drives, manufacturers are moving to a new technology known as “Advanced Format sector disk”. This technology requires the hard disk to be formatted and aligned in 4K sectors instead of the traditional 512 byte sectors that is currently used by most software. This article details the compatibility of these hard disk drives with Windows Home Server.


This article describes the two scenarios that can affect your installation of Windows Home Server. Some manufacturers provide alignment tools for their products; however these tools are not always compatible with the platform and technologies upon which Windows Home Server is built therefore we cannot provide support. You may consult hard disk manufacturers for their recommended solutions on adapting Advanced Format disks with various environments.

The next version of Windows Home Server will support Advanced Format disk in 512 emulated mode from most manufacturers and supports disks larger than 2 terabytes as storage disk, however Extensible Firmware Interface BIOS is required for the System Disk otherwise capacity exceeding 2 terabytes will not be utilized.

Scenario A: Server Disk

You install or replace your disk in your Home Server as a system disk or storage pool with an Advanced Format sector disk.

You may experience performance degradation and data reliability problems when using Advanced Format disk in your Home Server v1 for Server Backup, Storage Pool, or System Disk because there is no guarantee that IO operations will be aligned with the native sector size on the disk. Additionally, the disks may be formatted in a way that is not compatible with Windows Home Server.

Windows Home Server v1: Do not use Advanced Format disks in your Windows Home Server v1.

Windows Home Server ‘Vail’: Upcoming Windows Home Server codename ‘Vail’ will support Advanced Format disks as server disks.

For more information about Windows Home Server codename ‘Vail,’ click the following article number to view thwe article in the Microsoft Knowledge base:

2510009  (http://support.microsoft.com/kb/2510009/ )  Information about Microsoft support policy for large sector drives in Windows

Scenario B: Client Computers

You replace or restore a client computer with Advanced Format drives.

If you replace or restore a hard disk on a client computer with an Advanced Format disk drive, you should not see any issues with Windows Home Server functionality such as Backup and Restore feature.

Recommendation: Windows Home Server functionality is compatible with client computers using Advanced Format disk for Windows Home Server v1 and the upcoming version codename “Vail”.

Note: Windows 7 client users please see KB982018  (http://support.microsoft.com/kb/982018/ ) for more information.

Advanced Format Disk Drive

It is important to note that some hard disk manufacturers are releasing Advanced Format drives in the same base models as traditional 512 byte sector drives. Because of this, it is critical that you make sure that the drive you are purchasing is not an Advanced Format drive if you are running Windows Home Server v1. Before you purchase a disk drive, review the product specifications or visit the manufacturers Web site to ensure that the drive is compatible with Windows Home Server. Be aware that Advanced Format drives are not always clearly identified on the retail packaging.



  1. I got one for WHS in January. There was lots of divided opinion both ways. It s Samsung Spinpoint F4. It seems to be running fine at the moment.

    The hardware compatibility is a good selling point for Vail. 🙂

  2. I admit I haven't used WHS for very long, but I can not afford to take needless risks with my files. I was going to use WD EARS in my server but their tech support people talked me out of it. It is sort of like standing outside in a thunderstorm, you "probably" won't get it by lightning. But it is a heck of a hassle if you do get zapped. Two things that gripe me are that it can be impossible to find the info on the box and this is a heck of a time for Microsoft to issue the statement.

    1. Use the "hat" with single partition XP and you will be fine and compatible with WHS V1 because WD have the hat to automaticaly translate and adjust with that `hat` or switch if you please don't use the software and it is fully compatible with WHS v1 with that "hat" or switch if you prefer.

      1. It is somewhat moot at this point. I already exchaged them for non advanced format drives. The bottom line was that Western Digital Tech support, not Microsoft advised me against using AF drive on Home Server. I spent about 10-15 minutes discussing the options with them. They were very polite, but everything always came down to "do not use these drives with Home Server". They said many people used them, but more than a few experienced issues for unknown reasons. At that point, I felt it foolish to risk my data.

  3. Seems like a cop out position by MS and just another marketing opportunity to push Vail. It's interesting that they do not even touch on jumpering WD EARS drives.

  4. I had issues when I installed a WD EARS in my server – not a situation that I would like to repeat …

    1. Did you put the jumper on Pins 7&8? or run the utility. If you did neither then you would expect issues however if you did either you should not have encountered issues

    1. Same here, this is fud for scaring people of WD some won't be honest and won't post the 7-8 position jumper but will swear they did.

  5. Do Microsoft really think we are idiots! – We know what works and what doesn't in WHS 1.0 (we worked that out months ago, no thanks to Microsoft – and plenty of the Advanced Fomat drives work perfectly well in WHS 1.0. If they think we are going to move to WHS 2011 based on this KB they are dreaming!

  6. Miscrosoft WHS team manager: "So, any new strategies on how we can move units of Vail considering the pounding we're getting in the press over the DE fiasco?"

    Vail team member: "Let's formally warn users away from advanced format drives for v1 AND let's scare them further by implying they may never really know when they are going to buy one. They'll move to Vail just to avoid the "potential" loss of data. It can't lose."

    Vail team manager: "I love it. Let's get to it. While we're at it let's post another whitepaper on how fantastic RAID is. Oh and make sure we get all of those WHS v1 whitepapers on how bad RAID is removed from all our sites."

  7. 2 WD Green EARS 2TB (plus a few EADS's) in my SQA-5H. All fine after jumper install. I had one problem installing a new one 2 weeks ago, but it was the drive that was shot. A replacement (thanks Amazon) works like a treat.

  8. Bottom Line Up Front: MS has become a master at "Smoke and Mirrors"

    First I have 4 WDEARS 1.5 TB (pins 7 & 8 jumpered) in my server back up pool. The four drives are in a Mediasonice ProBox connected by eSata to a Sii 3124 port multiplier card (one single eSata port for all four drives) in a PCI (not PCI-Express) slot on an Atom 510 board (Gigabyte) to four of the six motherboard ports. I have 4 WDEARS 2.0TB (pins 7 & 8 jumpered) in my storage pool. There are four other drives (2 IDE and 2 SATA) connected to the other motherboard ports, including the system partition which is on a 500GB Seagate Momentus Hybrid Drive. The two IDE drives are Seagate 500GB IDE drives, and the remaining drive is a 1.5TB non advanced format Samsung drive.

    All works perfectly, back-up pool and storage pool. Duplication is on for all Shared Folders in the storage pool. Performance is exactly what it should be. I have no complaints and feel perfectly comfortable with my setup.

  9. I have two 1.5TB and one 2TB WD EARS. I ran the bootable CDROM with WDAlign rather than the jumper. Been working just fine for 1.5 years !! I'm sure its just scare tactics or they're just covering themselves because they can't be bothered regression testing on old software.

  10. Perhaps the issue with advanced drives isn't so much the fact that WHS 1 supports them, but what happens when something goes wrong? Sure they may run fine right now, but what happens when something unexpected occurs. Perhaps the drive extender is simply not up to par to deal with these disks after a failure? If you value your data, you wouldn't take such risks especially with drives >2GB! Clearly not a lot of folks here seem to care about that.

    1. Nice fud, same with should you build your own server and take a chance if you do a full backup of the server itself and using some inventive solution like XFiles from Drasha:):)

  11. I remember M$ giving us lots of ' we'll patch whs v1' when 2.5tb or 3tb drives appear so they can be used etc.

    Classic M$ , the patch is a less capable version of WHS , marvelous…

  12. I got lost in Microsoft's double-speak when I started clicking through to the KB entries. Can anyone answer this situation:
    I buy WHS 2011 and install it on a 2 TB boot drive. I then add 2 more 4 TB drives (yes, I know they don't exist yet). Will WHS 2011 be able to create a single 4TB NTFS partition on each of the data drives?

  13. I find it it hilarious that they are still referencing it by the name of Vail. Is one hand still not talking to another in that shit storm of a company?

  14. I've got 2 of the WD20EARS drives with pins 7 & 8 jumpered, one of them is in my HP EX470 case, and the other one is inside a Mediasonice ProBox 4 bay enclosure, no issues.

    I think the issue is that a lot of people probably don't read that message on the drive that tells them to jumper pins 7 & 8. Or they buy the drive OEM, don't have a jumper, plug it in without jumpering it, it works fine so they don't think they need to jumper it, until a few months down the road when performance issues start cropping up, then they start contacting Microsoft for support.

    1. Yes, so it's the customers fault. I'm not being sarcastic here, but let's face it. This problem could be solved by MS if they wanted to solve it. They don't. They know they've blown it with WHS 2, Vail or whatever the heck you want to call it, and this is another way to force users to switch. Hell, V2 isn't even out yet and they act like WHS 1 is an unsupported OS! It's ridiculous and it's just illustrative of why customers wish they could easily move away from MS products.

      1. They have solved it; it's called Server2008. Server2003 and anything based on it is old technology, move on and stop whining.

      2. Oh I agree with you that it's a problem that Microsoft should have fixed at least for the storage pool drives… I have to admit that I am really disappointed in Microsoft's support, or lack of support for WHS V1, seems like the community has always been kind of abandoned my Microsoft.

        Granted they probably couldn't have foreseen the need for drives using 4k sectors back when Win2k3 came out 8 years ago. But MS should do a better job of supporting new technologies considering that WHS V1 is an active product, and WHS V2 isn't out in production yet..

        I was just indicating that Microsoft is probably coming out with this statement now because they are probably getting an increasing number of support calls about these 4K drives, and don't want to deal with them, and so now they can point to a knowledge base article when people call for support.

  15. Here's the Windows / Windows Server support statement for Advanced Format and 4K drives – http://support.microsoft.com/kb/2510009

    WHS v.1 is built on Windows Server 2003. If WS03 doesn't support Advanced Format drives, it probably means the same must be true of WHS.

    The underlying problem with AF drives is that the file system and applications can do writes that aren't aligned with the real physical sector in the disk which causes the drive to do a read-modify-write, which kills performance (if it happens a lot). Most AF drives do read-modify-write in a volatile memory buffer, which means that if power is lost during the write, it is possible to lose more than just the data the app was writing.

    There's another KB out there with a pretty long list of fixes that were taken for Windows 7 and Windows Server 2008 R2 to support AF drives. Fixing old versions of Windows costs money – pretty sure that isn't something you do to market a new product.

  16. I just stumbled upon this article. I came to the site because today WHS decided to no longer see my 2TB WD Green. I powered off, pulled the drive out & made sure it works on another machin. I put it back in and now WHS backup service will not run. I try running the repair under Settings>Backup

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