Hotfixes For Hyper-V & Failover Clustering Can Be Confusing KB2496089 & KB2521348

As I’m building or extending a number of Hyper-V Clusters in the next 4 months I’m gathering/updating my list with the Windows 2008 R2 SP1 hotfixes relating to Hyper-V and Failover Clustering. Microsoft has once published KB2545685: Recommended hotfixes and updates for Windows Server 2008 R2 SP1 Failover Clusters but that list is not kept up to date, the two hotfixes mentioned are in the list below. I also intend to update my list for Windows Server 2008 SP2 and Windows 2008 R2 RTM. As I will run into to these and it’s nice to have a quick reference list.

I’ll include my current list below. Some of these fixes are purely related to Hyper-V, some to a combination of hyper-V and clusters, some only to clustering and some to Windows in general. But they are all ones that will bite you when running Hyper-V (in a failover cluster or stand alone). Now for the fun part with some hotfixes I’ll address in this blog post. Confusion Smile Take a look at the purple text and the green text hotfixes and the discussion below. Are there any others like this I don’t know about?

* KB2496089 is included in SP1 according to “Updates in Win7 and WS08R2 SP1.xls” that can be downloaded here ( but the Dutch language KB article states it applies to W2K8R2SP1

Artikel ID: 2498472 – Laatste beoordeling: dinsdag 10 februari 2011 – Wijziging: 1.0


Deze hotfix moet worden uitgevoerd een van de volgende besturings systemen:

  • Windows Server 2008 R2
  • Servicepack 1 (SP1) voor Windows Server 2008 R2
Voor alle ondersteunde x64 versies van Windows Server 2008 R2

04: 10

04: 05

When you try to install the hotfix it will. So is it really in there? Compare file versions! Well the version after installing the hotfix on a W2K8R2 SP1 Hyper-V server the version of vmms.exe was 6.1.7601.21642 and on a Hyper-V server with SP1 its was 6.1.7061.17514. Buy the way these are English versions of the OS, no language packs installed.

With hotfix installed on SP1


Without hotfix installed on SP1


To make matters even more confusing while the Dutch KB article states it applies to both W2K8R2 RTM and W2K8R2SP1 but the English version of the article has been modified and only mentions W2K8R2 RTM anymore.

Article ID: 2496089 – Last Review: February 23, 2011 – Revision: 2.0

For all supported x64-based versions of Windows Server 2008 R2


So what gives? Has SP1 for W2K8R2 been updated with the fix included and did the SP1 version I installed (official one right after it went RTM) in the lab not yet include it? Do the service packs differ with language, i.e. only the English one got updated?. Sigh :-/ Now for the good news: ** It’s all very academic because of this KB 2521348 A virtual machine online backup fails in Windows Server 2008 R2 when the SAN policy is set to “Offline All” which brings the vmms.exe version to 6.1.7601.21686 and this hot fix supersedes KB2496089 Smile. See where this is explicitly mentioned.

Ramazan Can mentions hotfix 2496089 and whether it is included in SP1 in the comments on his blog post but I’m not very convinced it is indeed included. The machine I tested on are W2K8R2 English RTM updated to SP1, not installations for the media including SP1 so perhaps there could also be a difference. It also should not matter that if you install SP1 before adding the Hyper-V role, so that can’t be the cause.

Anyway, keep your systems up to date and running smoothly, but treat your Hyper-V clusters with all due care and attention.

  1. KB2277904: You cannot access an MPIO-controlled storage device in Windows Server 2008 R2 (SP1) after you send the “IOCTL_MPIO_PASS_THROUGH_PATH_DIRECT” control code that has an invalid MPIO path ID
  2. KB2519736: Stop error message in Windows Server 2008 R2 SP1 or in Windows 7 SP1: “STOP: 0x0000007F”
  3. KB2496089: The Hyper-V Virtual Machine Management service stops responding intermittently when the service is stopped in Windows Server 2008 R2
  4. KB2485986: An update is available for Hyper-V Best Practices Analyzer for Windows Server 2008 R2 (SP1)
  5. KB2494162: The Cluster service stops unexpectedly on a Windows Server 2008 R2 (SP1) failover cluster node when you perform multiple backup operations in parallel on a cluster shared volume
  6. KB2496089: The Hyper-V Virtual Machine Management service stops responding intermittently when the service is stopped in Windows Server 2008 R2 (SP1)*
  7. KB2521348: A virtual machine online backup fails in Windows Server 2008 R2 (SP1) when the SAN policy is set to “Offline All”**
  8. KB2531907: Validate SCSI Device Vital Product Data (VPD) test fails after you install Windows Server 2008 R2 SP1
  9. KB2462576: The NFS share cannot be brought online in Windows Server 2008 R2 when you try to create the NFS share as a cluster resource on a third-party storage disk
  10. KB2501763: Read-only pass-through disk after you add the disk to a highly available VM in a Windows Server 2008 R2 SP1 failover cluster
  11. KB2520235: “0x0000009E” Stop error when you add an extra storage disk to a failover cluster in Windows Server 2008 R2 (SP1)
  12. KB2460971: MPIO failover fails on a computer that is running Windows Server 2008 R2 (SP1)
  13. KB2511962: “0x000000D1″ Stop error occurs in the Mpio.sys driver in Windows Server 2008 R2 (SP1)
  14. KB2494036: A hotfix is available to let you configure a cluster node that does not have quorum votes in Windows Server 2008 and in Windows Server 2008 R2 (SP1)
  15. KB2519946: Timeout Detection and Recovery (TDR) randomly occurs in a virtual machine that uses the RemoteFX feature in Windows Server 2008 R2 (SP1)
  16. KB2512715: Validate Operating System Installation Option test may identify Windows Server 2008 R2 Server Core installation type incorrectly in Windows Server 2008 R2 (SP1)
  17. KB2523676: GPU is not accessed leads to some VMs that use the RemoteFX feature to not start in Windows Server 2008 R2 SP1
  18. KB2533362: Hyper-V settings hang after installing RemoteFX on Windows 2008 R2 SP1
  19. KB2529956: Windows Server 2008 R2 (SP1) installation may hang if more than 64 logical processors are active
  20. KB2545227: Event ID 10 is logged in the Application log after you install Service Pack 1 for Windows 7 or Windows Server 2008 R2
  21. KB2517329: Performance decreases in Windows Server 2008 R2 (SP1) when the Hyper-V role is installed on a computer that uses Intel Westmere or Sandy Bridge processors
  22. KB2532917: Hyper-V Virtual Machines Exhibit Slow Startup and Shutdown
  23. KB2494016: Stop error 0x0000007a occurs on a virtual machine that is running on a Windows Server 2008 R2-based failover cluster with a cluster shared volume, and the state of the CSV is switched to redirected access
  24. KB2263829: The network connection of a running Hyper-V virtual machine may be lost under heavy outgoing network traffic on a computer that is running Windows Server 2008 R2 SP1
  25. KB2406705: Some I/O requests to a storage device fail on a fault-tolerant system that is running Windows Server 2008 or Windows Server 2008 R2 (SP1) when you perform a surprise removal of one path to the storage device
  26. KB2522766: The MPIO driver fails over all paths incorrectly when a transient single failure occurs in Windows Server 2008 or in Windows Server 2008 R2

Déjà vu Bug: The network connection of a running Hyper-V virtual machine may be lost under heavy outgoing network traffic on a computer that is running Windows Server 2008 R2 SP1

Anyone who’s been doing virtualization with Hyper-V on Windows 2008 R2 has a good change of having seen the issue described in

You install the Hyper-V role on a computer that is running Windows Server 2008 R2.

  • You run a virtual machine on the computer.
  • You use a network adapter on the virtual machine to access a network.
  • You establish many concurrent network connections, or there is heavy outgoing network traffic.

In this scenario, the network connection on the virtual machine may be lost. Additionally, the network adapter is disabled.
Note You have to restart the virtual machine to recover from this issue.

We’ve seen this one on VM’s that have indeed a lot of outgoing traffic.  In our environment the situation looks like this:

  • You can access the VM with Hyper-V Manager or SCVMM but not via RDP as all Network connectivity is lost.  The status the  guest NIS is always “Enabled” but there is no traffic/connectivity
  • You can try to disable the NIC but this tales a  very long time and when you try to enable it again this never succeeds. Disconnecting the NIC form the virtual network and connecting it again doesn’t help either.
  • You need to shut down the host but this takes an extremely long time, so long you really can’t afford to wait if it ever succeeds. It seems to hang at shutting down with a “non whirling whirly”.  So finally you’ll power off the VM and start it up again. Apart from entries related to having not connectivity the event logs are “clean” and there is no indication as to what happened.

Well this exact same issue is back with Windows 2008 R2 SP1. That’s the bad news. The good news is there is a hotfix for it already so you can fix it. You can read up on this issue in Knowledge Base article 2263829  and request the hotfix here. Instructions to get the hotfix are in there as well as a reference to the previous fixes for Windows 2008 R2 RTM.

Consider the following scenario:

  • You install the Hyper-V role on a computer that is running Windows Server 2008 R2 Service Pack 1 (SP1).
  • You run a virtual machine on the computer.
  • You use a network adapter on the virtual machine to access a network.
  • You establish many concurrent network connections. Or, there is heavy outgoing network traffic.

In this scenario, the network connection on the virtual machine may be lost. Additionally, the network adapter may be disabled.

  • You must restart the virtual machine to recover from this issue.
  • This issue can also occur on versions of Windows Server 2008 R2 that do not have SP1 installed. To resolve the issue, apply the hotfix that is described in one of the following Microsoft Knowledge Base articles:

    974909 ( ) The network connection of a running Hyper-V virtual machine is lost under heavy outgoing network traffic on a Windows Server 2008 R2-based computer
    2264080 ( ) An update rollup package for the Hyper-V role in Windows Server 2008 R2: August 24, 2010

Oh yeah, people often seem confused  as to where to install the hotfix. Does it go on the Hyper-V hosts or and/or on the guest?  It’s a hyper visor bug in Hyper-V so it goes on the hosts. Have a nice weekend.

KB2230887 Hotfix for Dynamic Memory with Windows 2008 Standard & Web edition does not apply to without Hyper-V editions?

As my readers all know by now, since I blogged about this here, you nee to install an update/hotfix for Hyper-v Dynamic Memory to work with Windows 2008 Standard & Web edition. You can find more information here:  Hyper-V Dynamic Memory does not work on a Windows Server 2008 Standard Edition or Windows Web Server 2008 virtual machine (VM)

UPDATE 2011/06/23: Microsoft released the hotfix based on end user feedback and you can download version 2 that works on all SKUs now (v2).

The cause is that on these versions of the operating systems the the required memory enlightenment is supported. After installing the hotfix (or SP1 in the case of Windows 2008 R2) memory addition enlightenment is available on these SKU and your good to go.

But recently I ran into an issue. One virtual machine guest on a a Windows 2008 R2 SP1 cluster that is running the Windows 2008 Standard edition without Hyper-V SKU, x86 the stand alone installer for Windows6.0-KB2230887-x86 throws following warning:


Windows Update Standalone Installer


The update does not apply to your system




That’s a bit strange. As you can see the hotfix has not been installed. And why would I need the with Hyper-V SKU to use dynamic memory with this guest?


I installed the same hotfix  without any issue on several Windows 2008 Standard Edition (the SKU with Hyper-V)  guests. So what is going on here? What exactly is different about the without Hyper-V SKU?  Note that Windows 2008 R2 no longer has such a SKU.  Microsoft states that it is an SKU for people who don’t need virtualization. Well as they installed it as a guest virtual machine they chose this version and now what? No hotfix for dynamic memory as a guest?



There is a TechNet forum discussion going on here where they have this issue and I asked them to check what SKU it was happening on. Bingo! It’s on the Windows 2008 Standard without Hyper-V version!

I don’t expect any Hyper-V functionality or management tools but I do expect to get the hotfix to enable Dynamic Memory in guests with this SKU, just like we get any other update that is relevant to Hyper-V, for example upgraded Integration Services. I’m going to ping a Microsoft contact on this one and see if they can help with this. And in case you’re wondering SKU = Stock Keeping Unit.

Upgrading a Hyper-V R2 Cluster to Windows 2008 R2 SP1

For all you people waiting to roll out Windows 2008 R2 SP1 to your Hyper-V cluster here’s a quick screenshot rich run through of the process. Some people claim you need to shut down the cluster services and shut down the guests but this is not the case.  You can do a rolling upgrade and your guests can stay on line on the other nodes, just use live migration to get them there. Now I do recommend to upgrade all the nodes tot SP1 as soon as possible and not staying a mixed Windows 2008 R2 / Windows 2008 R2 SP1 situation in your cluster. But this mixed situation makes upgrades of the nodes in the cluster possible without any down time for the guests (if you have live migration), which is the aim of having a high availability cluster.

Walk Through

Live migrate all the guests from the node you wish to upgrade to SP1. Make sure the host is fully patched and disable any antivirus services if you are running any. I always reboot the node before a major upgrade to make sure we have the server in a clean state with  no lingering reboots waiting  or processes can cause issues.

Navigate to the service pack 1 file for Windows 2008 R2, it’s called windows6.1-KB976932-X64.exe and start it up:



You’ll have to accept the license terms:



And then the preparation process starts:



It is now ready to start the upgrade and yes we want it to reboot automatically when needed:


The upgrade process takes a while (about 17 minutes on my lab servers):



When it’s done it will reboot and bring you back to the logon screen. Multiple reboots might be needed to complete the upgrade process depending on what’s running on your server. In this case we are dealing with dedicated Hyper-V nodes.

View when connected to the console


View when connected via RDP



After logging on you are greeted with this window:



And yes this is indeed the case


Reboot included the entire process took about 22 to 23 minutes. In the setup event log you’ll find these messages:

  • Initiating changes for package KB976932. Current state is Absent. Target state is Installed. Client id: SP Coordinater Engine.
  • Package KB976932 was successfully changed to the Installed state.

Note: if an extra reboot is required you’ll see an extra entry in between these stating: A reboot is necessary before package KB976932 can be changed to the Installed state.

When you have a cluster with nodes running both W2K8R2 TM and W2K8R2 SP1, mixed situation so to speak,  you’ll see the following notification in the cluster events:



You can live migrate the guest from the next node to the node already upgraded to SP1 and than repeat the process. You keep doing this until all your nodes are upgraded.


As a final recommendation I would suggest waiting until you get the SCVMM2008R2 SP1 bits is you use this product before you upgrade you clusters especially when using this with SCOM2007R2 PRO Tips. Otherwise you don’t need to wait just realize that until you have SP1 for SCVMM2008 R2 you won’t be able to use the new functionality for Hyper-V. In production I would not recommend using the RC1 for this.

Please do not forget to update your guests with the new SP1 version of the Hyper-V Integration Components. This is needed to be able to use the new features like Dynamic Memory & Remote FX. The Windows 2008 R2 RTM version of the Integration Components is  6.1.7600.16385:



You can do this using Hyper-V Manager through selecting “Insert Integration Services Setup Disk”  and running the setup, this will require a reboot.



Click to start the upgrade process:



It will ask to remove the previous version:



Work in progress:



Done and asking for a reboot:



SCVMM2008R2 can also be used, here you shut down the guest before updating the virtual guest services as it’s called in SCVMM2008R2. It can be annoying that the nomenclature differs. The good thing here is that you can upgrade multiple guest using VMM2008R2. Hans Vredevoort did a blog post on this here:  After the upgrade you can see that the version of the Integration Components  for Windows 2088 R2 SP1 is  6.1.7601.17514:


Windows 2008 R2 SP1 – RemoteFX Hardware To Get The Needed GPU Performance

When the first information about RemoteFX in Windows 2008 R2 SP1 Beta became available a lot of people busy with VDI solutions found this pretty cool and good news. It’s is a very much needed addition in this arena. Now after that first happy reaction the question soon arises about how the host will provide all that GPU power to serve a rich GUI experience to those virtual machines. In VDI solutions you’re dealing with at least dozens and often hundreds of VM’s. It’s clear, when you think about it, that just the onboard GPU won’t hack it. And how many high performance GPU can you put into a server? Not many or not even none depending on the model. So where does the VDI hosts in a cluster get the GPU resources? Well there are some servers that can contain a lot of GPUs. But in most cases you just add GPU units to the rack which you attach to the supported server models. Such units exist for both rack servers and for blade servers. Dell has some info up on this over here here. The specs on the  the PowerEdge C410x, a 3U, external PCIe expansion chassis by DELL can be found following this link C410x. It’s just like with external DAS Disk bays. You can attach one or more 1U / 2U servers to a chassis with up to 16 GPUs. They also have solutions for blade servers. So that’s what building a RemoteFX enabled VDI farm will look like. Unlike some of the early pictures showing a huge server chassis in order to make room to stuff all those GPU’s cards the reality will be the use of one or more external GPU chassis, depending on the requirements.