The Technology of WHS

Because WHS is a retooled version of Windows Server 2003, it's at times a sharp contrast to Vista, or even XP for that matter. Microsoft has attempted to put a lot of attention on WHS's headless operation mode, which allows a WHS server to run without a keyboard or monitor (but not a video card). For this purpose WHS is very much a server, as all administration tasks can be handled by the clients via a special Remote Desktop application while the server sits in a corner gathering dust. Microsoft even goes so far as discouraging use of the server directly both in the manual and on the warning dialog that pops up on the desktop of the server, in an effort to keep users inside the confines of the able but simple administrative client.

WHS also inherits Server 2003's low by modern standards system requirements, requiring as little as a 1ghz P3/Athlon processor and 512MB of RAM. Although systems shipping from computer vendors will be far more powerful, it's clear from the start that when it comes to the enthusiast market, Microsoft sees this as going on an old computer that's outlived its usefulness as a primary computer but is still well prepared for server tasks that will be limited by disk I/O and not CPU cycles or memory.

The final significant piece of technology to come over from Server 2003 is its security. By default WHS is locked down hard, bringing over the security enhancements that made Server 2003 harder to break into through a reduction in exposed services to attack. Microsoft is taking some liberties here in assuming that the server will be behind a naturally protected network with a NAT/firewall at the head. When properly configured, what is exposed to the internet (and not by default) is solely Internet Information Server 6.0, which has proven to be a hard target to break into (at least compared to the laughable IIS 5.0). Microsoft even goes so far as requiring strong passwords on any accounts that will be accessible from the internet (7 characters; uppercase, lowercase, and numeric characters required), which shows that some thought went into this.

Although Server 2003 predates Vista, the development team did manage to steal a handful of technologies from the fledgling operating system. Those tired of floppy disks will be ecstatic to find that Vista's far superior installation loader is used, allowing drivers to be loaded off of flash memory rather than floppy disks. The rest of the installer is still the traditional file-copy installer however, so WHS does not install quickly like Vista, although in Microsoft's defense users will ideally not be installing a server operating system as frequently.

Hardware and driver compatibility is something that needs to be mentioned as it's a natural result of using a server OS as the base. Simply put, a piece of hardware needs to be Server 2003 compatible to be WHS compatible. For critical components such as motherboards and video cards this shouldn't generally be a problem, although on the AMD side specifically there are some Athlon/Athlon-XP era boards that never got proper Server 2003 support. Many RAID controllers however aren't supported in spite of the availability of drivers due to WHS's unique method of handling disk drives.

Putting a new face on Server 2003 wouldn't be enough to make it capable of handling the duties of WHS in Microsoft's eyes, so among the new technologies in WHS and the one most paramount by far to its operation is what Microsoft is calling Windows Home Server Drive Extender (WHSDE). WHSDE is a new abstraction layer that sits between the various WHS services and the hardware, creating a common storage pool out of all of the available disks on the system, similar to the JBOD mode on some RAID controllers. This means that files & folders are no longer constrained by the size of any individual drive (from an end-user perspective you never even see things as drives, just folders) and instead WHSDE distributes files to drives based on how it believes space would best be allocated.

Furthermore, the storage pool is almost completely dynamic, in direct opposition to most JBOD/RAID setups. New drives can be added to the storage pool without disrupting the server, allowing the pool to be easily and continuously expanded to meet the data retention needs of the server. Drives can also be removed from the pool with a little more effort, as WHS can be informed to move all of the data off of a drive (assuming there's space elsewhere) so that the drive can be disconnected without interrupting the pool. While this isn't a completely new feature as various *nix systems have implemented similar features, this is the first we've seen it on Windows, and certainly in the running for the easiest to use implementation of such a feature.

Finally, WHSDE has a very interesting data protection feature that in many ways is a poor man's RAID 1, and yet smarter at the same time. By default WHSDE is constantly balancing all the drives so that no single drive is storing a larger percentage of data than another, so in the case of a drive failure the data lost will be an equal fraction of the data. More importantly however folders can be marked as needing additional protection (folder duplication), at which point WHSDE will make sure that the contents of that folder are on at least two separate drives when doing its balancing act. This is what makes WHSDE a poor man's RAID 1, as this balancing isn't done in real time and there's not immediately a copy of every single bit, but it's also smarter because this kind of protection is possible even among mismatched disks, disks on different controllers, external versus internal disks, etc. It offers slightly less protection than RAID 1, but as a tradeoff it's a lot more forgiving too.

At the end of the day WHSDE is really what makes WHS work and more than just a cut-down version of Server 2003. Just having a common storage pool alone makes WHS far easier to use with large amounts of data that don't fit on a single drive, and the extremely dynamic/forgiving nature of how drives and replication are handled becomes the distinguishing factor. WHSDE makes WHS far superior to any other version of Windows for storing and protecting data, and this is what gives it the ability to be a great server for home use. For enthusiasts, we suspect it will be the most attractive feature of WHS, for use as a file server.

It's also worth noting that this is the reason that WHS has very limited RAID support. Since all disks are assimilated by WHS, any RAID setups requiring configuration in Windows will fail. Only RAID setups done completely at the BIOS level (which normally requires higher-end RAID controllers) will work under WHS, and even then Microsoft discourages the use of such RAID setups in favor of the protection offered by WHS natively. RAID 5 users may want to ignore Microsoft on this however, as WHS's protection isn't as efficient as RAID 5, and it's slower due to WHS needing to balance data.

Index The Interface of WHS
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  • mindless1 - Wednesday, September 5, 2007 - link

    Ok, but want kind of soft-raid "needs" windows? I've dealt with several different soft raid controllers and windows official "support" is not needed, except for a management utility application if desired, to show the state of the arrays. While the management utility could be used to rebuild arrays, assign spares, etc, (in some cases), this is only supplimental to what functionality is provided in any typical soft-raid bios.

    Remember, windows can be installed onto a soft-raided volume. Soft raid doesn't depend on windows. There might be something about WHS that I haven't considered yet that would be a limitation but in general I find the article's conclusion that "not supported" means "won't work" to be odd. I think it more like when a cable ISP tells you that your router isn't "supported" meaning you're just on your own if you do it, they make no guarantee your unique configuration will or won't work.

    Let me put it another way, I am wondering if anyone has any example of a soft raid controller that can't be set up prior to OS installation, it's a pretty manditory feature if you want that OS on the RAIDed volume. What remains is a driver support for the controller in windows but any product with a Win2k3 driver should work unless MS has gone and deliberately castrated WHS. Likewise with a soft raid management utility, unless it's using a fancy installer which refuses to install due to not identifying the WHS OS.

    What I suspect is that MS simply disabled the OS integral raid functionality which would be used with drives NOT in any kind of raid controller (soft or hardware), raid configuration. If this is the case, someone will probably hack it to regain that functionality, and it might not even be anything more than a registry change needed.
  • leexgx - Tuesday, September 4, 2007 - link

    the idea if WHS is to be easy to use
  • ATWindsor - Tuesday, September 4, 2007 - link

    And? The simple functions can be easy to use, while at the same time having more advance features available if one turns them on.

  • leexgx - Tuesday, September 4, 2007 - link

    i assume thats what the add-ons are for later on when thay get made

    if an hdd failes or is about to on WHS it auto start balancing to an other disk thats Online and ok there is allways two copys if its turnd on (duplication)
    not not sure how to degrade an disk but i assume it try and move the data off it i know it will if you remove the problem disk Useing WHS connector as its part of the wizard when removeing disks

    the idea of WHS is for users who have limited lerning curves (Plug in expect it to work basicly)

    nothing stopping you from making RAID 5 on WHS but it not work correctly in WHS connector
  • mindless1 - Wednesday, September 5, 2007 - link

    The problem is that it is not real-time mirroring, since it waits until later to make the second copy, odds are you would end up losing something if a drive fails.

    I don't understand when people claim the idea here is "easy". What's so hard about plugging in two hard drives, entering a bios menu and assigning the two to an array? That's an order of magnitude easier than becoming accustomed to a new OS, setting it up. If the idea is just plug it in and expect it to work, then you will NOT HAVE that redundant second copy of the data you're implying is sufficient. These are fairly important features on a fileserver, and then if you want dynamic virtualized volumes that would be yet another feature so you can pick what you want to do, just like it is now with other windows versions where it is easy if you just accept the defaults, most basic config., but you don't have to accept the defaults.
  • leexgx - Wednesday, September 5, 2007 - link

    if

    as windows home server its an little lame that you cant use the Boot drive on hardware RAID 1 (boot disk for some resone Cant be SCSI drivers){Sata in raid or IDE RAID} as if the boot disk fails thats an big problem as there is no redundancy for it

    it more likey work after windows has been installed but its gettings WHS to Boot off an raid array after its been ghosted over all i can see is getting the driver to load up

    quote:

    To lose data 3 conditions would have to be met:
    1. Have to lose primary drive in WHS

    nope its stored on other disk that has been duplication as long as it has all ready been done if not you lose any new data thats just been put on (it have to be with in last 10secs to 1 min if it was an small file) unlakey that happen

    you can take the disks out and mount them as each disk uses norm NTFS file system just needs an drive letter putting on
  • tynopik - Wednesday, September 5, 2007 - link

    > as windows home server its an little lame that you cant use the Boot drive on hardware RAID 1 (boot disk for some resone Cant be SCSI drivers){Sata in raid or IDE RAID} as if the boot disk fails thats an big problem as there is no redundancy for it

    that is an annoyance for recovering the WHS, BUT if you were duplicating data, your data is still safe on another drive

    > nope its stored on other disk that has been duplication as long as it has all ready been done if not you lose any new data thats just been put on (it have to be with in last 10secs to 1 min if it was an small file) unlakey that happen

    it was very difficult to follow what what you're saying, but i think we both have the same understanding of how it works

    note i said ALL 3 conditions have to be met
    i agree losing primary drive alone will not mess up duplication, UNLESS condition 2 is ALSO met
    condition 2 is what you said, it fails before it had a chance to copy to the secondary drive, which i agree is very unlikely
  • tynopik - Wednesday, September 5, 2007 - link

    > The problem is that it is not real-time mirroring, since it waits until later to make the second copy, odds are you would end up losing something if a drive fails.

    1. it doesn't wait that long, you wouldn't lose much
    2. odds are you won't lose anything

    don't forget this is the BACKUP system, even if the BACKUP fails, your primary should still be ok.

    To lose data 3 conditions would have to be met:
    1. Have to lose primary drive in WHS
    2. (1) would have to occur in the narrow window between when it being copied to WHS and a duplicate is made onto another HD
    3. Have to lose ANOTHER drive in a COMPLETELY DIFFERENT system (the one the file was originally on)

    personally i would be more worried about the time between when a file is created/modified on your system and it is copied to WHS in the first place.

    Assuming backup runs at night and you create a file in the morning, that's almost a whole working day of exposure when the file is in ONLY one place

    > What's so hard about plugging in two hard drives, entering a bios menu and assigning the two to an array?

    having to limit yourself to the lowest common denominator of your drives

    let's say you have a 200gb, a 200gb and a 400gb drive and you put it in a raid, you're wasting half the capacity of the 400gb. With WHS you could store a full 400gb with duplication.
  • mindless1 - Thursday, September 6, 2007 - link

    Are you joking? I don't know what you think passes for reliable redundancy, but the idea that you're playing "odds" and then relying on a client not failing to keep your fileserver stores intact is crazy.

    This isn't a "backup", this is a "server", which for many people will be more important than their clients.

    Let's say you don't put a 200GB, 300GB and 400GB in a Raid, since you seem to be trying hard to cause a problem then thinking WHS would bail you out of ineptitude. The only thing hard about a server is when people make excuses not to use the time tested proven reliable strategies then try to excuse it with examples of bad choices. It is a very trivial thing to set up a home file server, far far quicker and easier than even a typical desktop WinXP system tweaked for a particular user's preferred environment. Trying to suggest there are problems is a sign you just don't understand this.

    For lower cost, any system can be made into a fully redundant fileserver that is more reliable, not in beta OS state, and has more storage until there is at least $360 more spent on drives. This 360 figure comes from 2x the initial $180 projected price of WHS.

    WHS will be a good option once 3 things are addressed:

    1) The price is too high for the small increase in functionality over what can be added as freeware or very low cost add-on to Win2k or XP.

    2) WHS matures more. I didn't run anything mission critical on any MS OS when it first came out, that would be foolish for an important fileshare. That it is derived from Win2K3 bodes well for it, but the very features being suggested as important by some, are the very features that are new enough to still have some beta-release related issues and need patched later.

    3) It is limiting in user choice of configuration. As OS is not supposed to tell you what to do, rather enabling you to do what you want to do.
  • tynopik - Thursday, September 6, 2007 - link

    > This isn't a "backup", this is a "server", which for many people will be more important than their clients.

    if your only/main purpose in getting this is as a server, then yes, perhaps WHS isn't for you

    it's most powerful/compelling feature is it's backup system. sure it can do other things, but if you aren't using that then there's not a whole lot of reason to use it

    just because backup of clients isn't a big deal to you doesn't mean it isn't a big deal to others

    just because WHS doesn't meet YOUR needs doesn't mean it's stupid, it just means it's not for you

    for me backing up clients is very critical and WHS looks like a godsend

    oh really?

    please tell me where i can find a backup system as flexible and powerful as this at no cost

    > For lower cost, any system can be made into a fully redundant fileserver that is more reliable, not in beta OS state, and has more storage until there is at least $360 more spent on drives.

    tell me which free system provides ALL of the following features and i will gladly jump on board

    - autocombine all physical disks into 1 volume
    - disks can be any size
    - disks can be added or removed at will
    - yet still have physical redundancy of files on different drives
    - automatically save single instance of identical files/blocks to reduce space wastage
    - automatically preserve previous versions
    - do live imaging of windows systems that can then be restored from bare metal with just a boot cd and a network connection

    sure parts of it can be duplicated for free, but do tell how you would setup something that does ALL that

    (just as a quick aside, a basic server just sitting there is going to waste a TON of space backing up multiple windows systems from all the redundant files. Oops, there goes all your extra space)

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