Archive for the ‘HYPER V’ Category

Migrate Pass-Through Disk storage attached hyper- v virtual machines

September 6, 2015 Leave a comment

Cause :

Pass through Disk attached Hyper-V virtual machine may not start and you receive a “‘Failed to Power on with Error ‘General access denied error’ (0x80070005)”.

Pass disk 3

Scenario :

Pass through disk  attached  hyper-v VM’s is failed to start when change storage systems or migrate to new host/cluster.

Resolution :

The above error is receive  when reattach pass through GUI from failover manager settings or Hyper-V manager. So need to add the disk using PowerShell with elevated permission.

Command syntax : Add-VMHardDiskDrive -VMName VMName -ControllerType SCSI -ControllerNumber 0 -DiskNumber 1 -AllowUnverifiedPaths -Passthru


Replace ‘VMName’ with your affected virtual machine. Get disk Number and controller number from disk management or failover cluster manager.


Hyper-V virtual Fibre Channel – Virtual machine direct storage array connectivity with HBA

June 15, 2015 Leave a comment

With windows 2012 and earlier OS , it can use virtual Fibre adapter feature to provide direct storage array connectivity from virtual machine

  • Optimal Storage performance and full protocol access
  • Supports guest clustering
  • Must use NPIV enabled HBA adapters and FC switches
  • Create Fibre channel SAN within hyper –v Virtual SAN manager
  • Use same virtual SAN configuration and naming convention on Hyper-V failover cluster environment

The below session describes how to configure a Hyper-V hosts to provision virtual machine with  virtual Fibre Channel adapter.

Platform : A servers with Hyper-V on Windows 2012 R2. Two Dual Port HBA Adapter is installed on this host.

Step 1 : Open Hyper-V manager – Virtual SAN manager- Create Virtual HBA ( VHBA1)  for first physical adapter as shown below:


Note: There are two Physical HBA is installed on host .So created Virtual HBA for first physical adapter. You can configure both HBA for redundancy

After Victual HBA is created , configure Virtual HBA controllers to the Virtual Server

From the virtual server settings – Add Hardware –Select Fibre channel Adapter

Assign the virtual Fibre adapter to the virtual server


Then next step is do the zoning on Fibre switch and register the host on storage array.

Hyper-V guest failover cluster- Provisioning Shared Virtual Disk

June 7, 2015 Leave a comment

This post describes how to create shared volume disk for virtual servers. Using shared disk feature easily can implement virtual server’s cluster known as guest cluster. Virtual hard disk allows to share same disk between multiple virtual machines and this ideal solution when host SQL 2012/2014 cluster in virtual servers.

Note: SQL 2012 and earlier version doesn’t support cluster shared volume (CSV) disks.

Virtualization Platform: Windows Server 2012 R2 Failover Cluster using Cluster Shared Volumes (CSV)

Step 1  :  Go to first guest Virtual machine from failover cluster manager.

Step 2: Add new VHDX virtual Hard Disk with desired size in the host CSV shared Disk

Example: C:\ClusterStorage\VolumeX, where C:\ represents the system drive, and X represents the desired CSV volume number.

Step 3: In the virtual machine settings, under SCSI Controller, expand the hard drive that you created in the previous procedure.

Click Advanced Features.

In the details pane, select the Enable virtual hard disk sharing check box.



Step 4: Go to the Second Guest virtual server and add the same VHDX files you created on the first Guest virtual server and share them also like in previous steps

Step 5: Login to first guest virtual server and then go to disk management

Step 6: Initialize the Bring the disk online, partition and format the drive with NTFS


Hyper-v virtual machines lose randomly network connections

January 14, 2015 Leave a comment

Issue :

Virtual machines running on hyper-v is randomly disconnected from networks. Live migration will restore network connectivity of affected Virtual machines

Affected Platforms :

Windows Server 2012 R2 Hyper-V & HP Servers


Disable VMQ on the physical network adapters on the host servers including teaming if any.


  • Open device manager
  • Expand each Network Adapters
  • Select network adapters and go to properties –Advanced- then select virtual machine Queues- then set value is disable
  • VMQ
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How to move hyper-V VM from windows 2008/R2 host to another host if its contain multiple AVHD files ?

August 24, 2014 Leave a comment


How to move hyper-v VM to another host if its contain multiple AVHD files. Read more…

Categories: HYPER V Tags:

Hyper-V host Server Memory Sizing

March 10, 2014 Leave a comment

Last week , I do a quick research on how to size memory ( RAM ) for the hyper v host .There is no real documentation about what should you reserve for an Hyper-V Host because it totally depends what you are running on it.

Here is a blog which talks about windows 2008 R2 hyper v host. But you can use this formula as approach

In summary, Hyper-V host memory can be sized based on following formula.

384MB + 30MB per 1GB of physical memory on the host machine.

At the end I am calculating it for my LAB Server which has 256 GB RAM memory:

(384MB + 30MB* 256 )= 8064 . So can reserve 8 GB memory for the host which has 256 GB

But again it’s just an approach to size hyper v host and you need to monitor your servers because this count differs based on the scenarios

Categories: HYPER V Tags:

windows 2012 based failover cluster console crash and hanging

June 10, 2013 1 comment

Recently, I added a node to existing windows 2012 based failover cluster. Everything went normal , but failover cluster console is getting crash and generating error as below .


The issue is caused by applying the update 2750149. MS released hotfix to repair the issue . Please install hotfix 2803748 to repair the issue

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