Here's another guest post from Jeremy Hagan, thanks again Jeremy!

If you are planning on using High Availability for Hyper-V there are a number of things to keep in mind while planning your deployment and there are a number of best practices that will impact on your planning.  I will cover the best practices first then discuss how these impact your pre-deployment decision making.

Best Practice 1 – One VM per LUN

High Availability in Hyper-V is provided through WS08 Failover Clustering.  When you fail-over a cluster resource with a dependent disk that disk can only be active on one cluster node at a time.  So if your cluster disk has more than one VM on it, then they must all fail over as a group.  Essentially there is nothing wrong with this, so long as you know what you are doing when you decide to go down this path.  The benefit of one VM per LUN is that you have the best granularity in terms of moving workloads between cluster nodes for maintenance or for smoothing out performance bottlenecks.

Imagine if you had 5 VMs running on one LUN in a 5 node cluster.  One of your cluster nodes is over-utilized and one is under-utilized.  If you were to move the 5-VM group to the under-utilized node then you might end up moving the bottleneck.  If the 5 VMs were split you could fail them over individually.  This would allow you to smooth out the utilizations more evenly.

Best Practice 2 – Fixed VHD files

VHD files can be Dynamic (i.e. the VHD is the size of the data in the VHD) or Fixed (i.e. the VHD is the size of the data and free space).  Having Fixed VHD files confers a performance benefit since there is no requirement to continually allocate new space to the VHD file.  Fixed VHD files also prevent performance issues caused by file fragmentation (especially when combined with one VM per LUN).

With these two best practices in mind I will now explain how they may affect your planning decisions around LUN sizing for a HA Hyper-V cluster.  My first attempt at planning my LUN sizes consisted of monitoring the physical servers I was going to virtualize for a period (in my case, three weeks) and extrapolating their observed data growth out to 3 years’ worth and then adding a 15% premium.  After that I rounded up to the nearest 5 GB and then ordered my LUNs from the SAN team.

My first mistake was that I forgot to factor in the amount of memory I planned to allocate to each VM in the calculations (a real beginner's mistake).  The next thing I didn’t think about until it came time to implement was that even though you might have a Fixed VHD file with 5 GB of free space inside that file, as soon as you take a snapshot, that 5 GB of free space becomes immediately inaccessible since now all changes are written to a differencing VHD file until the snapshot is deleted. 

So if you decide to go for both of the above best practices you really need to think hard about, not only  your LUN sizes, but also your management practices regarding snapshots.  In my environment I have decided that no Production VM will be allowed to run on a snapshot beyond a certain period.  So if you decide to make a snapshot of a VM prior to making a change, once the change is accepted and you have decided not to revert, then the snapshot should be deleted.  This will cause the changes to be committed to the original VHD on the next reboot.

If you decide to ignore best practice number 1 make sure you do it with your eyes open.  Know what you are getting yourself in for and have a bailout plan ready.  Oh and if you do ignore BP #1 I wouldn’t recommend ignoring BP #2.  The benefits of pooling VMs on a LUN are significant.  It simplifies your SAN configuration, reduces the chances that you will run out of drive letters on your parent partition and best of all you don’t have to make as many hard decisions about locking away disk space.  You can just go ahead and create a 1 TB LUN and start putting VMs on it, run with as many snapshots as you like and not worry.  Until you start to reach a performance bottleneck that is.

In summary, think hard about sizing your LUNs.  Consequences of under-sizing are significant, no room for snapshots, no room for boosting the amount of memory allocated to a VM.  If you have the luxury of copious amounts of SAN space (hey storage is cheap, right?) then overspec.

Notes:

• If you want to put more than 1 VM on a LUN and don’t want to have to write a script to do it, then you will want this hotfix (actually you will want it anyway, since the other changes in functionality it enables are invaluable for long term operations).
• If you group clustered VMs on a single LUN, don’t shut down the OS from within the OS or from Hyper-V Manager, this is not a cluster-aware shutdown and counts as a failure.  The OS will be restarted by the cluster and then if you go “what the ?!?!” and shut it down again, depending on how the cluster resource is configured this will induce a failover to another node, taking the rest of your VMs with it.  Try explaining that outage to your boss when a business critical server goes out of action for a couple of minutes at a crucial period because you shut down a scratch VM you had been using to test some software.  I for one do not feel like having to get a change request authorized just to shut down a machine.  Once you have made a VM a clustered VM, ALWAYS use Failover Cluster Management or the SCVMM Console to shut it down.

I recently recorded a podcast with TechNet's Social Platform team, discussing the social platform, and the new TN social bookmarking in particular.  Listen to the podcast, and then leave feedback here.

Some points to think about:

1. Build authority: I'd follow mark russinovich's bookmarks, wouldn't you?
2. Reciprocity: the more I mark, the more value I add to you, and verse-vicea <network effects>
3. Proactivity: If you and I share a topology, say exchange on windows, and I notice in your marks that you've had FOO problem, but I haven't...yet... I can go check out the solution and maybe avoid the problem in the first place
4. De-Silo-fication: the solution to my users's email problem may lie in the exchange silo on TN, or the OWA/Outlook silo, or in the ISA silo, or - maybe in all three. Once I find the content I need, I can tag all three with the same tag (let's say "EXCHANGE RANGERS") and then find them again much faster if I ever need to. More importantly, YOU can find them, and maybe you hadn't thought to look in the ISA silo.
5. Pathfinding: For example, the hot Hyper-V topic now has a filterable, living database of the most popular links related to Hyper-V, along with an RSS Feed for Hyper-V. When you find a great site on this or any other topic, you can use the bookmarklet to tag it with the topic name (e.g. "hyper-v" and/or "deployment"). As of the launch, 40% of the bookmarks are not on Microsoft domains.

Check out the TechEd video Windows Server 2008 Hyper-V: Scripting & Programmatic Management for Fun & Profit (VBS & PowerShell) by John Kelbley, and Alexander Lash.

Some of John's example script are newly posed in the Official Scripting Guys Forum!, for example:

• Script to Start All VMs on a Hyper-V Server
• Script to List all VMs on a Hyper-V Server
• Script to Turn Off all Hyper-V VMs
• Script to Save State on all Running Hyper-V VMs
• Script to Start a VM?
• Script to Pause all Hyper-V VMs

Thanks to John for sharing these.

By default, the free-as-in-beer Microsoft Hyper-V Server 2008 is configured for manual updates. In other words, it is NOT configured out of the box to go fetch automatic updates. This is desired behavior for most installs. However, if there are critical issues, like those you might find on the secbuls page, then you must remember to go manually update your Hyper-V Server.

Let's go do that right now.

No, really, stop what you are doing and go patch your Microsoft Hyper-V Server 2008 boxes right now. Here's how:

• From the command line type HVCONFIG
• Type 6 and press ENTER to search for updates.
• Type Y and press ENTER to download and install all updates.

Note: This may take some time.

You may be prompted with “A restart is required to complete Windows Updates. Restart now?” Click Yes to initiate a restart. By default, running virtual machines will automatically be saved prior to restarting the Hyper-V Server.

For more info see http://www.microsoft.com/downloads/details.aspx?FamilyID=2a429ea3-e33b-414f-ae49-2eead9f5b351

Think of it as a contest. Have a Hyper-V blog post you want to share with the world, but no place to post it? Send it to me, I'll post the best ones here and send the lucky blogger a prize from the vast pool of Microsoft swag we keep in a room on the second floor. Send your post to tonyso@microsoft.com.

In the scripting forum someone :-) asked:

"Can anyone suggest the way to create AzMan scopes for VMs (I can assign VMs to scopes) with Powershell/WMI/VBScript?"

4 scripts are provided for managing your AzMan scopes in Hyper-V:

CreateVMInScope

DisplayVMScopes

ClearVMScopes

ChangeVMScope

Enjoy!

John's blog post describes free-as-in-beer training materials you can download and reuse with your users, including an intranet SharePoint site so users can self-serve. These are based on the materials Microsoft IT provides to Microsoft employees.

http://blogs.technet.com/john_westworth/archive/2008/10/08/everyday-productivity-education-epe.aspx

The zip download file contains a model of the intranet site for your own use with editable content in the EPE Docs folder. When you customize the documents, the HTML model will link automatically to the guides updated to fit your environment.

• Guide List for Windows XP and 2003 Microsoft Office System
• Guide List for Windows Vista and 2007 Microsoft Office System
• Intranet Site Model Zip Download (74.0 MB)

There is a new TechNet Edge screencast from Jeff Alexander demonstrates Microsoft Hyper-V Server 2008. OBTW, Microsoft Hyper-V Server 2008 is free-as-in-beer.

The RoboChamps is similar to the DARPA Urban Challenge, only it is a SIM. Participants must program a robotic car to navigate to a series of checkpoints in an urban environment. 

Check out the website for the software, challenge kits, training materials, and a video podcast: www.robochamps.com.

You know those little dishes beside cash registers marked "Give a penny, take a penny"? It is one manifestation of the "pay-it-forward' meme. I give an extra penny from my transaction change now when I don't need it, and I take one later when I do.

Folks who follow the Getting Things Done methodology are always looking for the equivalent in action mangement. An easy example: so that you won't forget to take the <important thing> with you in the morning, put it in front of the door before you go to bed. See what I mean?

Anyway, in that spirit I offer this little insight into an invaluable time-saving  Outlook 2007 feature if you have RM installed We do here at Microsoft: on the Permissions menu. select Do Not Reply All, and you have saved everyone on the mail the time it takes to delete all the replies if they are not interested in the thread.

Well we can claim it anyway - the next version of Windows is named... Windows 7 :-)

Read about it on Mike Nash's blog post: Introducing Windows 7.

Watch Chris Slemp's video* for an overview of TN/MSDN's "social platform" that includes:

Social Bookmarking

Community Content (ak.a. "wiki") - for example see http://technet.microsoft.com/en-us/library/cc753637.aspx

Forums - for example, did you know the Scripting Guys have a forum?

Blogs

Code Gallery

Oh yeah, search is now part of the social platform

*Hey, who's profile is that on the screen at about timecode 2:07?

In the coming months it will be even more important for IT to show how it adds value to the company. One way to add value is to shave costs, Microsoft can help:

• Get Virtual Now -  Reduce server hardware acquisition and maintenance costs with Windows Server 2008 and Hyper-V 
• Reduce management costs with SCVMM  and Microsoft System Center
• Lower desktop deployment and management costs by deploying Microsoft Desktop Optimization Pack and Application Virtualization
• Socialize your IT department - make maximum use of the new developments on TN/MSDN, such as Social Bookmarking, Forums, CodePlex*. Community Content
• Train up with Microsoft Assurance Learning Benefits
• Embrace virtual travel - You can radically educe travel and communications costs with Microsoft Unified Communications solutions
• Embrace Green IT - save money on power
• Finance it with Microsoft Financing
• Outsource it to Microsoft - Microsoft Online Services can reduce you total cost of ownership

*For instance, did you know there is a free-as-in-beer library of PowerShell cmdlts for managing Hyper-V on  CodePlex?

Did you notice that the URL for search on TechNet changed recently?

It is now social.technet.microsoft.com/search.

Check out the new "refinements" (that work like "filters", only, I guess "filters" sounds too prole...) and the "Related To:" listings that bring you "pre-refined" searches, nifty.

Bothered by English-language results being categorized higher on the search results page than non-English results? Check out the new ability to exclude English results. 

Follow the Rob Veliz blog for more info.

Have a listen to this podcast on SEO with Rob Veliz, then check out these tools:

Keyword Research: https://adwords.google.com/select/KeywordToolExternal

Keyword Research: tools.seobook.com/keyword-list/generator.php

Link Research: http://siteexplorer.search.yahoo.com/

Analytics: adCenter Add-inBeta for Excel 2007

Webmaster tools: http://webmaster.live.com/

The Springboard content series on TechNet has a blog. AFAIK this is the first time a content series has started a blog, as opposed to a product group. Check it out and keep an eye on it around the PDC timeframe for announcements and information about planning and deploying Windows 7.

Here's looking forward to an "Exchange Administrator's Guide blog", or a "Windows Server 2008 ResKit blog" or, (my favorite) a "PowerShell Command Line Reference blog".

The TN and MSDN social platform, including the new bookmarking apps, just went virtual to improve perf as more and more IT Pros and Devs twig to what's going on. Read about it on Chris's blog post. 24 VMs and growing...

Live search continues to rock the "free-as-in-beer images while you search" game. Wow!

Think of it as fire-and-forget ammo for those afflicted with "I am my brother's keeper" syndrome.

Splogbane: If you are reading this on a blog other than http://blogs.technet.com/tonyso, why not stop patronizing a splog and come over to the original?

Marcus Anthony and Scott Bullens have a startup that makes me sad/glad. Sad we need it, glad it is there. My Mobile Witness allows you to use the camera in your phone and text messaging to send a photo of someone (or, say a license plate) that can be retrieved by law enforcement without a warrant. This can be a powerful deterrent.

Say a friend leaves a party with a person they've just met against your advice and having had too much to drink. You snap their pic and inform them you expect your friend to get home safely, if they don't the authorities will have the info they need to follow up.

The service is free - but there will be ad-support in their somewhere I'm sure.

You already read my blog post about MAP 3.1, right?  The beta of the newest version Microsoft Assessment and Planning (MAP) Toolkit (3.2) is available on Connect, including new modules: