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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  • ATWindsor - Monday, September 10, 2007 - link

    And if one drive in a raid5 goes corrupt, you can still accsess the data. That doesn't mean you can't mess it up to the point where additional recovery is needed, and its the same with WHS, you can stand to loose one drive, but no problems "bigger" than that.

    Thats not the point, the point is that for you to have "hot-spare-functionality" as you talk about on WHS, you still need to have that amount of aditional free space, so having that dta will cost you extra HD-psace, just as having a hot-spare will. Depending on usage, WHS will need more or less free space than a hot-spare drive will provide.

    You might think it's little point having redundancy on backups, i feel like it's worth it. If one doesn't feel the need for this redundancy, the duplication-system in WHS isn't that useful either (that if if you don't want to risk having all your data on a single machine).

    To repeat the point yet again, the system should be more flexible, there are of course quite a few people who don't need the extra functionality, but there is also quite a few that want's to have smething easy to set up, but still maintain some features and flexibility.
  • Gholam - Monday, September 10, 2007 - link

    Thing is, however, on first glance RAID5 is very alluring - on paper, you get great performance, high reliability, and minimal loss of usable HD space.

    However, in practice, it is far, far more complicated, expensive and dangerous - but your typical home user doesn't have the depth of experience to know that.

    Therefore, if you absolutely must have a RAID5 setup, just buy a controller, set up WHS on a single large volume and disregard its drive pooling features.

    As for myself, I'm currently planning replacing my system which is getting a bit long in the tooth to handle the latest games. It's an A64 3200+ on ASUS A8N with 3GB RAM and GF6800GT, housed in a CM Stacker case. So, since upgrading a S939 CPU is currently next to impossible, once WHS is available over here (Israel, supposed to arrive sometime in october-november) I'm planning to build a new system, and in this one, replace the graphics card with something passively cooled (7100/8400), stick in a bunch of drives (probably 4x500GB) and run WHS drive pool on it. I considered getting a hardware RAID5 controller, but after examining my options, dismissed the idea as too expensive - I can get 3-5 extra 500GB drives for the price of a decent RAID5 card with cables. With room for 12 HDDs in the case, 8 SATA + 2 PATA connectors on the motherboard and ability to expand via USB/Firewire, I don't see this system capping out anytime soon.
  • ATWindsor - Monday, September 10, 2007 - link

    I agree that raid5 has some pitfalls, but once (properly) setup, I think it's pretty easy to handle, just stay away from it until a drive goes down, and then replace it :)

    However I would still like to have it implmented in WHS, if needed under some kind of "advanced setup", one has to activate.

    Personally I use a 16-port-hardware-controller, with the same controller also in my off-sote backup-computer. It might be over the top, but I find it worth the convinience when i have well over 10 sata-drives, restoring from backup is a hassle, so it's nice to be able to handle a single drive going down without having to get everything from the backup, and you get added security aggainst file-corrption when the cache has battery-backup (and also, the preformance is good, but that is not so important, only nice :))

  • Gholam - Monday, September 10, 2007 - link

    16-port hardware controllers are nice, but I can't justify sinking $800+ into one, not on my budget.
  • n0nsense - Thursday, September 6, 2007 - link

    hm ...
    raid 5 corrupted ?
    search google for "raid 5 corruption".
    the only thing that real threat is 2 or more dead disks simultaneously.
    WHS redundancy duplicate files over several disks, which mean that you waste as much space as in mirror.
    advantages - different disk sizes.
    disadvantages - performance.
    hard to believe that some one will think to mix IDE SATA and SCSI disks for file server (actually i do mix as i have 2 mirrored 36GB SCSI drives @ 15k rpm for system 2 mirrored 500GB SATA drives for sensitive (in terms of redundancy) data and 250GB SATA drive for temp files, incoming, and other things that i don't care about).
    Once i used raid 5 of 4 74GB SCSI for about 3 years 24/7/365 with almost constant load, then it was replaced with bigger SATA drives when one of them died without loosing 1 bit of my data.
    more probably you'll put 2-6 really big (250-750GB) disks for such purpose. smaller will go to the boxes.
    you wont run dedicated box for less then 3 clients.
    so for the same space price you can set up hardware raid 1, probably get more performance (controller dependent), 0.0004% failure rate.
    depends on where you live, WHS price save (~180 USD) will give you about 2x250GB or 1x 500GB SATA drives + SATA to PCI card with RAID support.
  • archer75 - Thursday, September 6, 2007 - link

    Performance isn't a disadvantage here. All of your data is copied to a single drive at first. Think of it as a holding area. Data is then analyzed and moved off of that to where it needs to be. So as far as you are concerned you are only transfering to one single disk.
    The performance is good enough for me to stream a HD movie off of it. So it's good enough.

    If you are running a RAID array with constant usage for years then it seems WHS is not marketed for you.
  • n0nsense - Friday, September 7, 2007 - link

    it's right, but even at my home with only 2 users, i can see much more load on disk performance.
    restoring something, can be done @ 30MBps or @90.
  • tynopik - Thursday, September 6, 2007 - link

    > the only thing that real threat is 2 or more dead disks simultaneously.

    you're naive

    power outages (either from power company or blown power supply, controller errors, driver errors, there are a ton of things that can mess up RAID5. RAID5 is very fragile in the sense that if you mess up just a bit of it's structure, the entire thing is shot.

    > 0.0004% failure rate

    did you read that article i posted? try closer to 20-30% in the real world (now that doesn't necessarily mean data loss, but problems nonetheless)

    > disadvantages - performance.

    for backup this isn't really an issue
    plus when copying between computers you're going to be limited by your own harddrive

    i need to backup a bunch of laptops (which don't contain raid obviously) daily so WHS is definitely NOT going to be a bottleneck
  • tynopik - Thursday, September 6, 2007 - link

    here's what i pulled from ONE thread">

    "I have had these drives configured as a RAID 1 array ever since I built the computer.

    I built this system 15 months ago, then 10 months ago I experienced a severe RAID failure (i.e. I lost all my data). "

    "I have exactly the same problem on my Asus K8N (NForce3) mobo."

    andy b
    "I also have the identical problem."

    "I'm going through this exact problem right now"

    "I don't think I have very good news for you all. Windows does SEEM to be running ok, but I have a bunch of little quirky problems. When I brought Outlook up for the first time, it said my mailbox was corrupted, so I pulled that from my backup. Word had a problem with the Norton said it's settings were corrupt and reset to the defaults. And who knows about the stuff I haven't seen yet.

    So, I'm reluctantly coming to the conclusion that I need to reformat and re-install. I'm also thinking about pulling an old IDE drive from one of my spare parts computers to use as a backup drive and backing up my full system weekly and my data daily. The sad part is, that's why I bought a MB with RAID 1 capability, so I wouldn't HAVE to do this."

    "it happened to me for the third time this morning"

    "So frustrating to lose my computer for a couple hours every week or so to rebuild my friggin' hard drive (when it doesn't even really need it!!!)"

    "I've had this happen 3 times now with 2 different versions of the drivers."

    "i saw this raid drive split thing once."

    Mile Hy
    "Guess what...Over the week end I got the infamous red message about the Raid degrading."

    "Same problem here, today"

    "The same thing just happened to me"

    "I also got blasted by this mysterious raid degraded bug last week for no apparent reason."

    "have the same issues on my machine with an ASUS K8N"

    "Had same problem flasing red degraded."

    "I am getting the red flashing "degraded" message from NVidia at boot."

    "now i have this problem also....degraded data"

    "Over the past few months I have had 4 instances of nvraid dropping 1 drive"

    "the first test trying to copy data from the raid to the external firewire drive resulted in not 1 but 2 drives dropping out."

    notice that last line, copying data to an external firewire drive caused TWO drives to drop out. If he had had that in RAID5 that would have been disastrous.
  • n0nsense - Friday, September 7, 2007 - link

    funny, but we are arguing about almost everything.
    of course there is a lot of problems and failures.
    the 0.0004% about raid1. 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.
    hardware problems will do the same to your system and its really does not matter what you running inside.
    of course i can give you examples of corporate Data Centers with 0 data loss, but we are talking about home.
    and you can build cost effective system that will do the same.
    let's organize it from worth to best.
    no raid
    soft raid
    raid 1
    raid 1+0 or 0+1.
    about forums. you will not find many happy user of raid there. Simply because they don't need until they have a problem.
    My SATA raid build on build-in controller which is part of Asus P5N32-E SLI, based on Nvidia 680i chipset.
    Indigo (part of HP) with about 1000 press machines monthly out, using integrated intel's matrix storage controllers for raid (1 and 0) (they use standard HP wx4000). This press machines working at full load non stop 24/7/365. Year @ IT department, no problems with raid.
    the big problem is moving raid array to another type of controller (new MoBo for example).here soft raids have big advantage.
    again the main question is "Shall you or shall not pay 180 USD for WHS"
    for not very advanced user i will recommend Debian box with Bacula to manage backups, syncing, share etc.
    You will have fully functional machine where file/backup server can be the only task, or it can be only one of other features like gaming machine, workstation, mail server, ftp server(not fake server ), DNS, DB server (yes, there is a use for it at home. for example media library of Amarok can use it ), media server and media center, web server, and stream server. You will not limited by MS greediness, but by your need and will.
    all of it or even more can run on single box when we talking about home. it was time that i had 7 computers at home for only 2 people, now it's only 2.5 (can't call P II 400MHz 186MB ram laptop computer, but it perfectly extends media and internet to balcony for nice Saturday breakfast with sea view).
    i do like some MS products like Office, but when it come to OS, DB, servers, use real one.

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