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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  • Gholam - Sunday, September 9, 2007 - link

    Cheap motherboard-integrated controllers corrupt and outright lose RAID arrays all the time due to driver bugs, and performance is atrocious. I won't trust a RAID5 array to anything that costs less that $500, and for that price, you can just stick a few extra drives for duplication.
  • n0nsense - Sunday, September 9, 2007 - link

    I did with LSI MegaRaid 500 with 128MB cache (originaly come with 32).
    I found it in second hand store for 50$ :)
    actually you can buy new one scsi320 for ~300$
    as for sata, there is IBM ServerRAID 7t, HP, adaptec and other controllers for ~300$
    starting price of 150$ for 4 port SATA II controllers.
    Personally, i prefer raid 10, but the problem is were to put the disks.
    i already have 5 and only 1 empty slot left. (3x5.25 reserved for future water cooling)
  • n0nsense - Sunday, September 9, 2007 - link

    I did with LSI MegaRaid 500 with 128MB cache (originaly come with 32).
    I found it in second hand store for 50$ :)
    actually you can buy new one scsi320 for ~300$
    as for sata, there is IBM ServerRAID 7t, HP, adaptec and other controllers for ~300$
    starting price of 150$ for 4 port SATA II controllers.
    Personally, i prefer raid 10, but the problem is were to put the disks.
    i already have 5 and only 1 empty slot left. (3x5.25 reserved for future water cooling)
  • Gholam - Sunday, September 9, 2007 - link

    A 5 year old controller that you pick up at a second hand store is not something that I - or an OEM - can base a line of products on. A new RAID5 controller which is not built by Promise or Silicon Image will run you $500+ - the ~$300 solutions are ZCR cards that are basically addons to $500+ motherboards. ServeRAID 8s costs around $700, HP P400/256 nearly $600, well over $800 for P400/512. A bigger case to store extra drives - or a few external USB/Firewire/eSATA enclosures - will run you much less.
  • tynopik - Friday, September 7, 2007 - link

    > power outage is not on option when we talking about some kind of server.
    don't tell me, that UPS is something you don't use.

    1. ups is not something most home users will use, you have to design assuming it won't be there
    2. even if you do have ups, what happens when the batteries die? often the only warning you will get is one day the power flickers and the system shuts off. do you replace all batteries every 2 years whether they need it or not?
    3. even if you meticulously maintain your ups, the internal power supply can still go bad

    > hardware problems will do the same to your system and its really does not matter what you running inside.


    ntfs by itself is fairly fault tolerant. you yank the power you might lose a file, but everything else is fine

    raid5, you yank the power you might lose EVERYTHING

    that is why WHS file duplication is far safer and better

    > of course i can give you examples of corporate Data Centers with 0 data loss, but we are talking about home.

    of course i said it works if you're using ENTERPRISE LEVEL HARDWARE everywhere. Good raid cards start at $300. A $150 motherboard with onboard raid doesn't even begin to cut it.

    > let's organize it from worth to best.
    > no raid
    > soft raid
    > raid 1
    > raid 1+0 or 0+1.

    there is no such thing as 'best'
    there is 'best for a particular set of requirements'

    maybe your requirements are such that your best looks like that

    my best would like
    soft raid
    raid 1
    no raid
    raid 1+0 or 0+1

    (that's right, i would rather have no raid than 1+0 or 0+1)

    > This press machines working at full load non stop 24/7/365. Year @ IT department, no problems with raid.

    congratulations, you are one of the 70% who didn't have problems with their raid last year. Are you confident you won't be one of the 30% next year?

    > for not very advanced user i will recommend Debian box with Bacula to manage backups, syncing, share etc.

    not very advanced users aren't going to have a clue about Debian
    not very advanced users are going to be setup up raid properly
  • n0nsense - Sunday, September 9, 2007 - link

    Any UPS have connection to computer and will shut it down properly when configured to do so.

    As for controllers. I was surprised to find that almost all integrated raid controllers (including my), actually software and not hardware. So need to admit you were right about it. (I spent few hours to transfer my disks to Promise ST150 TX4 and rebuild the raid).

    NTFS is the best in Microsoft's world. but since we can't run Windows on ext3 or reiserfs, or Linux on NTFS, we can't actually compare them in real world benchmark. Theoretically, NTFS is inferior. Actually any modern FS of all desktop systems is good enough.

    So we still at the same point.
    I agree with you that WHS is good for redundancy (if you enable this option) where you don't want to use real raid controller with "small" price tag.

    But I just can't see justification to use it. Compared to alternatives it does not have something spacial enough to pay extra 180 USD. Yes I know that for most of users, Linux is something horrifying. But we are not talking about them, but about the WHS and alternatives. in this case about raid.

    by the way, i'm very curious. what raid 1+0 or 0+1 did to you ? :)
    that remind me to answer. shut down will cause you to lose open/unsaved files in any scenario. but it can also damage you entire HD. raid 5 will give you better redundancy then SINGLE disk(single data instance). but when duplicating, raid 1 is the best.
  • n0nsense - Thursday, September 6, 2007 - link

    nForce (i'm not sure, but i think there is intel's chipset based MoBos with raid 5) raid still better in terms of stability, redundancy and performance then any soft raid.
    think what will happen if your WHS will crush unrecoverably.
    how will you restore your data ?
  • n0nsense - Thursday, September 6, 2007 - link

    Hello, if you have important things that you don't want to get lost or corrupted by some virus or anything else, do your self a favor and check">">
    or any other user friendly distro.
    you will find a way better solutions for home (and not only) server.
    more exactly you'll find OS capable to be everything with more then proven stability and security.
    and yes, it will work inside your MS environment. as for file server (and this is main purpose of home server), you will find much better performance.
    You may want to extend it to be your media server. means really distributed one. server with tv card and clients on other boxes.
  • tynopik - Thursday, September 6, 2007 - link

    > as for file server (and this is main purpose of home server)

    no, the main purpose of WHS is backup

    if your main purpose is just a simple file server then yes, WHS probably isn't for you
  • mindless1 - Saturday, September 8, 2007 - link

    Absolutely not. A server is not backup, it would be a very foolish thing to keep your back as an online windows box.

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