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Virtual Machine Snapshots: The useful tool that will drag you down.

Note: Once again I accidentally scheduled a technical article to publish on a holiday.  In honour of Canadian Thanskgiving I am republishing this article on Tuesday. -MDG

The Story:
One of my clients called me and asked me why some of their servers were running so terribly slow.  Actually, that’s not entirely true… they told me that they were working on Server1, Server2, and Server3 and all three needed more CPUs and more RAM.  Because we live in a virtual world, this is easy enough to accomplish.  It took me all of five minutes to accomplish this for the three servers, and that included the time it took me to walk back to my desk via the coffee machine.

I did not respond so hastily when over the course of the next few weeks I was asked to increase the resources again… and again.  What are you guys doing, trying to run NASA?  No, we are developers working on our tools, and they are just too slow!

Rather than increase the resources again I decided to do some investigating.  I wanted to see why these computers (servers with 12GB of RAM and 2 quad-core virtual CPUs) were running so slow… and yes, I checked to make sure that it was not just greedy users who wanted more more more, the computers really were running – no, that is the wrong term – they were crawling slower than they should have.

SnapshotsAfter checking several possibilities over the next few days I figured out that somebody had taken VM snapshots of these servers – rogue VM snapshots, because there actually is a written company policy about the proper and acceptable use of VM snapshots – months earlier, and they had just continued to grow… like mold.

The Methodology
The way VM snapshots work – and I should mention at this point that they work about the same in VMware as in Hyper-V – is that the virtual memory and hard drive files are paused, made read-only, and delta files are made for both.  You will not see any difference from within the virtual machine – the memory will continue to work as it had, as will the hard drive – but the files that comprise the virtual machine will change.


The snapshot file will continue to grow… and grow… and grow.  As you can see from this image, the file is at about 12.5GB in size.  Not too bad, right?  Well look at this:


Did I forget to mention that while the Virtual Memory snapshot file is shown in Datastore Browser, the actual delta files are not (just like the Flat files are hidden).  This is what we see when we connect to the host and look at what is going on under the hood.

This VM Snapshot is less than an hour old.  Over time the file will grow… to ridiculous sizes.  And yes, eventually your virtual machine will slow down… and then crawl… and then, eventually, it might stop.  However if you were to look at your performance monitors, both from within and from outside the virtual machine, the performance baselines will look perfectly normal.  The performance of course will not, and that is where things get dicey.

So Why Use Them?
Virtual Machine Snapshots (or Checkpoints, as Microsoft has taken to calling them) are a great tool when used responsibly.  They should never be considered a long-term solution to anything.  What they are is a great way to step forward into the unknown… you have a change to make, a patch to apply, a program (or even an operating system) to upgrade, and you are worried that something will corrupt.  Before going ahead with the change you can take a VM Snapshot, make the change, and once you have confirmed that it worked you can delete the snapshot.  If the change did indeed hork something, you can revert to the moment in time before you started, and all is good.

…But don’t keep them longer than you need to!
I mentioned that the client in question has a written company policy about the proper and acceptable use of VM snapshots.  That is for a couple of reasons:

  1. If you follow the policy, you don’t just take a snapshot – you name it and make notes.
  2. When only one person takes the snapshots, that person can keep a diary of what snapshots there are; they can know who requested them, and they can then follow up with the requesting party to make sure they can be deleted.

When rogue administrators (Have I mentioned before how I loathe letting anyone who doesn’t need administrative rights have administrative rights?) take snapshots without following the proper procedures – which includes deleting the snapshots when they are no longer needed, then you will run into problems.  However when the proper policy is followed, this will never become an issue.

VM Snapshots: Good or Bad?
Just like any potentially dangerous tool, the answer is both good and bad.  When used properly they are great, but with time they become rotten to the core.

How do I know if I have them?
If you spend any amount of time in vCenter, you know that there is no simple way to determine what VM snapshots are in your environment… short of going into the Snapshot Manager for each VM and checking.  However if you are an avid reader of this blog you may have caught an article I wrote a little over a year ago called How do YOU Manage?.  IN it I mentioned a tool I love called RVTools.   Among the myriad reports it will generate for you is one called vSnapshot, and when you use it while connected to your vCenter environment it will list all of the snapshots you have.


You can download it from http://robware.net/.  While it is free (Rob calls it ‘Nice to haveware’) there is a Donate button, and although it is in Dutch, it will allow you to donate through PayPal.  I just did by the way… as a way of saying Thanks! to Rob for the hard work he puts into it that I was then able to benefit from!

If you use PowerCLI (also discussed in the article) there is a way to get the same information in PowerShell, which is:

get-vm | get-snapshot | format-list

…And for those of you running System Center Virtual Machine Manager and not vCenter Server, there is a PowerShell script for you too.  It is available here, and is a free download from the TechNety Script Library.

I have been telling people for years that Snapshots/Checkpoints are good but dangerous.  As I always say: If you cannot measure it, you cannot manage it.  Using these tools will allow you to measure, manage, and then eliminate VM Snapshots in a timely manner… before they become a problem.

Converting Fixed Size VHDs to Dynamic Sized VHDs

I was called in to help a company recently with a small Hyper-V environment.  They created a 2TB VHD file (they had good reasons for not using .vhdx files, but the steps in this article will work for both versions). 

They realized that they had unnecessarily created the drive as a 2TB Fixed Size disk rather than a Dynamically Expanding disk.  While there are no real performance differences between the two in Server 2012 R2, when it comes to portability, the dynamically expanding drives have a huge advantage.  When they realized that they were planning for a SAN upgrade, the IT Administrator decided to take the preemptive step of converting the disk.

It’s actually pretty easy… In the Hyper-V menu you click on Edit Disk…, and when the Edit Virtual Hard Disk Wizard comes up you go through the steps of selecting the appropriate file, and on the Choose Action screen select the radio button Convert.  On the next screen you specify the destination file, which eventually is where the problem is going to lie.  But for now you enter the filename, click Next, then click Finish to begin the process.

For those of you who are PowerShell fans, you can accomplish the same task by running the following cmdlet:

Convert-VHD D:\Hyper-V\HardDisk.vhdx -DestinationPath D:\Hyper-V\NewHardDisk.vhdx -VHDType Dynamic

Great.  Now you go into the settings of your virtual machine, point it to the new file, and boot it up.

Microsoft Emulated IDE Controller (Instance ID
{83F8638B-8DCA-4152-9EDA-2CA8B33039B4}): Failed to Power on with Error ‘General access denied error’
IDE/ATAPI Account does not have sufficient privilege to open attachment
‘D:\Hyper-V\NewHardDisk.vhd. Error: ‘General access denied error’
Account does not have sufficient privilege to open attachment
‘D:\Hyper-V\NewHardDisk.vhd. Error: ‘General access denied error’

Un-oh.  That doesn’t look good.  I click on the option to see the details, and it expands to the following:

‘VMName’ failed to start. (Virtual machine ID
‘VMName’ Microsoft Emulated IDE Controller (Instance ID
{83F8638B-8DCA-4152-9EDA-2CA8B33039B4}): Failed to Power on with Error ‘General access denied error’ (0x80070005). (Virtual machine ID
‘VMName’: IDE/ATAPI Account does not have sufficient privilege to open attachment D:\Hyper-V\NewHardDisk.vhd. Error: ‘General access denied error’ (0x80070005). (Virtual Machine ID 1DC704C1-6075-4F6C-B364-AFE4947304F3)
‘VMName’: Account does not have sufficient privilege to open attachment
D:\Hyper-V\NewHardDisk.vhd. Error: ‘General access denied error’ (0x80070005). (Virtual Machine ID 1DC704C1-6075-4F6C-B364-AFE4947304F3)

Alright, it looks like I have a file permission error.  When I look at the Security tab on the Properties window of the source VHD file I see the following:


Great… all I have to do is add that user (group?) to the new VHD file, and I’ll be set.  The problem is… how the heck do I do that?  I certainly can’t do it from the GUI… No problem. 

  1. Open a Command Prompt with Administrator credentials.
  2. type the following command: icacls “D:\Hyper-V\NewHardDisk.vhd” /grant “NT Virtual Machine\1DC704C1-6075-4F6C-B364-AFE4947304F3”:F
  3. The response should read:

processed file: D:\Hyper-V\NewHardDisk.vhd
Successfully processed 1 files; Failed processing 0 files

If this is what you got, then you are ready.  You should now be able to start up your virtual machine without error.

Good luck… now go forth and virtualize!

A VMware Gripe


Okay, I can’t delete a file.  Any Level 1 systems administrator would look at this message and say: ‘Okay, VMware is not allowing me to delete an ISO file.  Very likely the ISO file is connected to a virtual machine.’

Ummm… but WHICH virtual machine is it?  Gee thanks, vCenter, I have scores of VMs… would it have been that tough to put into the DETAILS section (see the empty space next to the STATUS section) exactly which virtual machine or virtual machines this ISO is connected to?  Would that really have been a difficult thing to program into your system?

I didn’t think so.

Fortunately, I have my RV Tools that lets me know what’s what… it made my life slightly easier this week as I prepare to redeploy my SAN Smile

Hyper-V 2008 R2: Still good enough?

I manage a vSphere environment at work, and it is a real change from the last few years when I spent all of my time talking about Hyper-V.  I want to be clear – it is not better or worse, it is just… different.  We have a number of virtualization hosts, plus a physical domain controller, and one physical server running Windows Server 2008 R2 (Enterprise), which has an app running that precludes us from changing that.  The app hardly uses any memory, so a lot of that was wasted.

While my physical server does not have a lot of RAM (8GB) it has a ridiculous amount of internal storage… I mean terabytes and terabytes of it.  I asked my boss about it, and he said it was there for something that they no longer use the server for… but it’s there… wasted as well… for now.

A few weeks ago I proposed a project that would require use of that space, and it was tentatively approved.  The problem is that the existing application and the proposed application are not supposed to co-exist on the same server.  I would have to come up with a way to segregate them.  No problem… I would install the Hyper-V role onto the physical server, and then create a new virtual machine for my purposes.

Once I explained to my boss that no extra licensing was required – because the physical server is licensed for Windows Server 2008 R2 Enterprise Edition, we could build as many as four virtual machines on the same license on that host – he got excited, and asked the usual ‘what else can we do?’ questions.

‘Can we cluster the virtual machine?’

No.  I mean, we could, but it would require having a second Hyper-V host which we do not have.  There is nothing we can do about that without incurring extra costs… and the purpose of the exercise is to do it for zero dollars.

‘Can we use Storage Spaces?’

No.  Storage Spaces is a great technology – one that I really loved talking about when I was working with Microsoft.  However it is a feature that was only introduced in Windows Server 2012, and we are only on Server 2008 R2.

‘Can we create the VM using 64TB .vhdx drives?’

No.  Again, .VHDX files were only introduced in Windows Server 2012.  We are limited to 2TB .VHD files… which is more than enough for our actual needs anyways.

‘How about UEFI Boot on the VM’

Nope.  Generation 2 hardware was introduced in Windows Server 2012 R2, so we are stuck with Generation 1 hardware.

So after he struck out on all of these questions, he asked me the question I was expecting… ‘Then why bother?’

I became a fan of Hyper-V as soon as it was released in Windows Server 2008.  Yes, the original.  I was not under any delusions that it was as good as or better than ESX, but it was free and it didn’t require anything to install… and if you knew Windows then you didn’t need to learn much more to manage it.

Of course it got much better in Windows Server 2008 R2, and even better in the SP1 release… and then in Windows Server 2012 it broke through, and was (in my opinion) as good as or better than vSphere… in some ways it was almost as good, in some ways it was better, and in the balance it came out even. Of course Server 2012 R2 made even better improvements, but when I spent three years with Microsoft Canada – first as a Virtual Partner Technology Advisor and then as a Virtual Evangelist – criss-crossing the country (and the US and the globe) evangelizing Hyper-V in Windows Server 2012 I was confident when I said that at last Microsoft Virtualization was on a par with VMware.

I would never have said that about Hyper-V in Windows Server 2008 R2. Sorry Microsoft, it was good… but vSphere was better.

However in this case we are not comparing Microsoft versus VMware… we are not deciding which platform to implement, because VMware is not an option. We are not even comparing the features of vOld versus vNew… because vNew is still not an option.

All we are deciding is this: Does the version of Hyper-V that is available to us for this project good enough for what our needs are for the project? Let’s review:

  • We need to create a virtual machine with 4GB of RAM. YES.
  • We need that VM to support up to 4TB of storage. YES. (We cannot do it on a single volume, but that is not a requirement)
  • We need the VM to be able to join a domain with FFL and DFL of Windows Server 2008 R2. YES.
  • We need the virtual machine to be backed up on a nightly basis using the tools available to us. YES

That’s it… we have no other requirements. All of our project needs are met by Hyper-V on Windows Server 2008 R2. Yes, Microsoft would love for us to pay to upgrade the host operating system, but they got their money for this server when we bought the license in 2011, and unless they are willing to give us a free upgrade (there is no Software Assurance on the existing license) and pay to upgrade the existing application to work on Server 2012R2 then there is nothing that we can do for them… and frankly if we were in the position where we were going to have to redeploy the whole server, it would be on VMware anyways, because that is what our virtualization environment runs on.

I spent two years evangelizing the benefits of a hybrid virtualization environment, and how well it can be managed with System Center 2012 R2… and that is what we are going to have. I have purchased the System Center licenses and am thrilled that I will be able to manage both my vSphere and my Hyper-V from one console… and for those of you who were paying attention that is what I spent the last three years recommending.

I can hold my head up high because I am running my environment exactly how I recommended all of you run yours… so many of my audience complained (when I was with Microsoft) that my solutions were not real-world because the real world was not exclusively Microsoft. That was never what I was recommending… I was recommending that the world does not need to be entirely VMware either… the two can coexist very well… with a little bit of knowledge and understanding!

Another tough exam…

As a subject matter expert (SME) on virtualization, I was neither excited nor intimidated when Microsoft announced their new exam, 74-409: Server Virtualization with Windows Server Hyper-V and System Center.  Unlike many previous exams I did not rush out to be the first to take it, nor was I going to wait forever.  I actually thought about sitting the exam in Japan in December, but since I had trouble registering there and then got busy, I simply decided to use my visit to Canada to schedule the exam.

This is not the first exam that I have gone into without so much as a glance at the Overview or the Skills Measured section of the exam page on the Internet.  I did not do any preparation whatsoever for the exam… as you may know I have spent much of the last five years living and breathing virtualization.  This attitude very nearly came back to bite me in the exam room at the Learning Academy in Hamilton, Ontario Wednesday morning.

Having taught every Microsoft server virtualization course ever produced (and having written or tech-reviewed many of them) I should have known better.  Virtualization is more than installing Hyper-V.  it’s more than just System Center Virtual Machine Manager (VMM) and Operations Manager (OpsMgr).  It is the entire Private Cloud strategy… and if you plan to sit this exam you had better have more than a passing understanding of System Center Service Manager (ServMgr), Data Protection Manager (DPM), and Orchestrator.  Oh, and your knowledge should extend beyond more than one simple Hyper-V host.

I have long professed to my students that while DPM is Microsoft’s disaster recovery solution, when it comes down to it just make sure that your backup solution does everything that they need, and make sure to test it.  While I stand behind that statement for production environments, it does not hold water when it comes to Microsoft certification exams.  When two of the first few questions were on DPM I did a little silent gulp to myself… maybe I should have prepared a little better for this.

I do not use Service Manager… It’s not that I wouldn’t – I have a lot of good things to say about it.  Heck, I even installed it as recent as yesterday – but I have not used it beyond a passing glance.  The same used to be true of System Center Orchestrator, but over the last year that has changed a lot… I have integrated it into my courseware, and I have spent some time learning it and using it in production environments for repetitive tasks.  While I am certainly not an expert in it, I am at least more than just familiar with it.  That familiarity may have helped me on one exam question.  Had I taken the time to review the exam page on the Microsoft Learning Experience website I would have known that the word Orchestrator does not appear anywhere on the page.

Here’s the problem with Microsoft exams… especially the newer ones that do not simply cover a product, but an entire solution across multiple suites.  Very few of us will use and know every aspect covered on the exam.  That is why I have always professed that no matter how familiar you may be with the primary technology covered, you should always review the exam page and fill in your knowledge gaps with the proper studying.  You should even spend a few hours reviewing the material that you are pretty sure you do know.  As I told my teenaged son when discussing his exams, rarely will you have easy exams… if you feel it was easy it just means you were sufficiently prepared.  Five questions into today’s exam I regretted my blasé attitude towards it – I may be a virtualization expert, but I was not adequately prepared.

As I went through the exam I started to get into a groove… while there are some aspects of Hyper-V that I have not implemented, those are few and far between.  the questions about VHDX files, Failover Clustering, Shared VHDX, Generation 2 VMs, and so many more came around and seemed almost too easy, but like I told my son it just means I am familiar with the material.  There were one or two questions which I considered to be very poorly worded, but I reread the questions and the answers and gave my best answer based on my understanding of them.

I have often described the time between pressing ‘End Exam’ and the appearance of the Results screen to be an extended period of excruciating forced lessons in patience.  That was not the case today – I was surprised that the screen came up pretty quickly.  While I certainly did not ace the exam, I did pass, and not with the bare minimum score.   It was certainly a phew moment for a guy who considers himself pretty smart in virtualization.

Now here’s the question… is the exam a really tough one, or was I simply not prepared and thus considered it tough?  And frankly, how tough could it have been if I didn’t prepare, and passed anyways?  I suppose that makes two questions.  The answer to both is that while I did not prepare for the exam, I am considered by many (including Microsoft) a SME on Hyper-V and System Center.  I can say with authority that it was a difficult exam.  That then leads to the next question, is it too tough?  While I did give that some thought as I left the exam (my first words to the proctor was ‘Wow that was a tough exam!) I do not think it is unreasonably so.  It will require a lot of preparation – not simply watching the MVA Jump Start videos (which are by the way excellent resources, and should be considered required watching for anyone planning to sit the exam).  You will need to build your own environment, do a lot of reading and research, and possibly more.

If you do plan to sit this exam, make sure you visit the exam page first by clicking here.  Make sure you expand and review the Overview and Skills Measured sections.  If you review the Preparation Materials section it will refer you to a five day course that is releasing next week from Microsoft Learning Experience – 20409A- Server Virtualization with Windows Server Hyper-V and System Center (5 Days).  I am proud to say that I was involved with the creation of that course, and that it will help you immensely, not only with the exam but with your real-world experience.

Incidentally, passing the exam gives you the following cert: Microsoft Certified Specialist: Server Virtualization with Hyper-V and System Center.

Good luck, and go get em!

Counting Down the Classics with the US IT Evangelists


On the first day of Christmas my true love gave to me…”

Ninety-nine bottles of beer on the wall…”

“Thirty-five articles on Virtualization…”

Pale AleAll of these are great sing-along songs, whether for holidays, camping, bus-rides, or comparing virtualization technology.  Each one is a classic.

Wait… you’ve never heard the last one? That’s okay, we are happy to teach it to you.  It has a pretty catchy tune – the tune of cost savings, lower TCO, higher ROI, and a complete end-to-end management solution.

Even if you can’t remember the lyrics, why don’t you open up the articles – each one written by a member of Microsoft’s team of IT Pro Evangelists in the United States.

You can read along at your own pace, because no matter how fast or slow you read, as long as you are heading in the right direction then you are doing it right! –MDG

The 35 Articles on Virtualization:

Date Article Author
12-Aug-13 Series Introduction Kevin Remde – @KevinRemde
13-Aug-13 What is a “Purpose-Built Hypervisor? Kevin Remde – @KevinRemde
14-Aug-13 Simplified Microsoft Hyper-V Server 2012 Host Patching = Greater Security and More Uptime Chris Avis – @ChrisAvis
15-Aug-13 Reducing VMware Storage Costs WITH Windows Server 2012 Storage Spaces Keith Mayer – @KeithMayer
16-Aug-13 Does size really matter? Brian Lewis – @BrianLewis_
19-Aug-13 Let’s talk certifications! Matt Hester – @MatthewHester
20-Aug-13 Virtual Processor Scheduling Tommy Patterson – @Tommy_Patterson
21-Aug-13 FREE Zero Downtime Patch Management Keith Mayer – @KeithMayer
22-Aug-13 Agentless Protection Chris Avis – @ChrisAvis
23-Aug-13 Site to Site Disaster Recovery with HRM Keith Mayer – @KeithMayer
25-Aug-13 Destination: VMWorld Jennelle Crothers – @jkc137
26-Aug-13 Get the “Scoop” on Hyper-V during VMworld Matt Hester – @MatthewHester
27-Aug-13 VMWorld: Key Keynote Notes Kevin Remde – @KevinRemde
28-Aug-13 VMWorld: Did you know that there is no extra charge? Kevin Remde – @KevinRemde
29-Aug-13 VMWorld: A Memo to IT Leadership Yung Chou – @YungChou
30-Aug-13 Moving Live Virtual Machines, Same But Different Matt Hester – @MatthewHester
02-Sep-13 Not All Memory Management is Equal Dan Stolts – @ITProGuru
03-Sep-13 Can I get an app with that? Matt Hester – @MatthewHester
04-Sep-13 Deploying Naked Servers Matt Hester – @MatthewHester
05-Sep-13 Automated Server Workload Balancing Keith Mayer – @KeithMayer
06-Sep-13 Thoughts on VMWorld Jennelle Crothers – @jkc137
09-Sep-13 Shopping for Private Clouds Keith Mayer – @KeithMayer
11-Sep-13 Dynamic Storage Management in Private Clouds Keith Mayer – @KeithMayer
12-Sep-13 Replaceable? or Extensible? What kind of virtual switch do you want? Chris Avis – @ChrisAvis
13-Sep-13 Offloading your Storage Matt Hester – @MatthewHester
16-Sep-13 VDI: A Look at Supportability and More! Tommy Patterson – @Tommy_Patterson
17-Sep-13 Agentless Backup for Virtual Environments Special Guest Chris Henley – @ChrisJHenley
19-Sep-13 How robust is your availability? Kevin Remde – @KevinRemde
20-Sep-13 VM Guest Operating System Support Brian Lewis – @BrianLewis_
23-Sep-13 How to license Windows Server VMs Brian Lewis – @BrianLewis_
24-Sep-13 Comparing vSphere 5.5 and Windows Server 2012 R2 Hyper-V At-A-Glance Keith Mayer – @KeithMayer
25-Sep-13 Evaluating Hyper-V Network Virtualization as an alternative to VMware NSX Keith Mayer – @KeithMayer
26-Sep-13 Automation is the Key to Happiness Matt Hester – @MatthewHester
27-Sep-13 Comparing Microsoft’s Public Cloud to VMware’s Public Cloud Blain Barton – @BlainBar
30-Sep-13 What does AVAILABILITY mean in YOUR cloud? Keith Mayer – @KeithMayer

…and as for me? Well it’s pretty simple… just go to www.garvis.ca and type Virtualization into the search bar.  You’ll see what I have to say too!

Hyper-V CPU Compatibility Mode

it is pretty well known that for Live Migration to work in Hyper-V, the CPUs on the hosts must be of the same family (Intel to Intel, AMD to AMD).  However it is not as simple as that. 

Both companies are constantly improving their products, so a CPU that Intel makes in 2013 will have more features than one they made in 2010, and because of that they will not be compatible for Live Migration.  In theory then, the Live Migration window is really closer to eighteen months before you are out of band.

So how impractical would it be if both VMware and Microsoft told companies that in order to have Live Migration their servers had to be less than eighteen months apart?  So several years ago Intel and VMware got together and addressed the problem.  The result was what they called Enhanced vMotion Compatibility (EVC).  Essentially what they do for servers in a cluster where EVC is enabled is they simply mask the advanced features of the newer CPUs, which are usually only needed for sound and video and thus not for the majority of business servers.

Microsoft then introduced Hyper-V, and overnight (five years later) they are a real player in the virtualization realm.  In fact, there are some people who would say that they are equal to or better than VMware.  They need to implement a similar feature to prevent the same issue.  Unfortunately they can’t call it EVC because that includes VMware’s trademark vMotion.  Being better with technology than they are with marketing, they settled on calling it ‘Migrate to a physical computer with a different processor version…’ or MTAPCWADPV.  Try to say that three times fast ;)

While their feature name is nowhere near as easy as the equivalent from their competition, the technology is applied to the virtual machine rather than to the cluster.  So in your environment you could have a cluster where some VMs could migrate to some hosts but not to others.


Now here’s the misconception: People seem to think that by enabling MTAPCWADPV you are sacrificing performance on your VMs.  Nothing could be further from the truth. 

The performance reduction of CPU compatibility mode is a myth.  What MTAPCWADPV does is it masks the newer features of the CPU – mostly multi-media signatures and such – but does not otherwise hobble the CPU.  Unless your VM requires those newer features there will be absolutely no performance decrease to the VM.  If they have VMs that DO need the newer CPU features then leave those on the newer blades.

The other myth, of course, is that it allows you to Live Migrate from Intel to AMD or vice versa.  Unfortunately that is not possible.  Will it be in the future?  Who knows… but under the hood the two families are still different enough that I don’t expect to see it anytime soon.

  1. So now that you know, go enable MTAPCWADPV!  Here’s how:
  2. Open the Settings window of your VM
  3. Expand the Processor section.
  4. Click on Compatibility.
  5. Select the check box called Migrate to a physical computer with a different processor version.

That’s it!  The only caveat is that the VM must be turned off before you do it.  Messing with the processor is not something you want to do live ;)

Live Migration can be performed between any servers with compatible CPUs… as long as they are within the same family.  Try it yourself!

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