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Tuesday, April 22, 2014

Remove Unwanted Checkpoint By Using Powershell


In today post, we are going to look on how to check and remove unwanted checkpoint created by user. In my scenario, we do encountered customer who love to create a checkpoint and some till multi-level nested checkpoint . Eventually problem wont start now but soon you may encounter problem such as:-

  • Unable to boot up virtual machine due to lack of free hard disk space. Each time we create a checkpoint, avhd file is created and this occupied hard disk space.
  • Virtual machine performance start to degraded. Once an avhd file is created, your VM will act like differencing disk which consist of parent disk and child disk. Every new data write into the VM will store in avhd file.
  • Corruption occur due to unavoidance circumstance. In order to boot up the VM, you may need to create a new virtual machine configuration and merge existing checkpoint. When this happened, most likely 50% , you will encountered data lost.

Do take note that Checkpoint must handle with care and not meant to replace your backup solution.

Best practice when using checkpoint

  • Don’t leave the checkpoint on your system for quite sometimes.
  • Remove unwanted checkpoint after finish testing and when no longer require.
  • Do be careful when revert snapshot as you may encountering data lost. Make sure, no new data is coming into the VM after create a checkpoint
  • Avoid using checkpoint as backup solution. Use DPM or third party backup software to protect your virtual machine and application data.

Now let look on how to check if checkpoint exist on your virtualization environment:-

For single VM

  • Use Hyper-V Manager snap-in to verify.

For multiple VM, it will be east if we use Powershell

  • Use Powershell Get-VMSnapshot cmdlet
Get-VMSnapshot –VMname *


In my scenario above, we identified which virtual machine consists of checkpoint and also when is the creation time.

Well, time to do some clean up!

Execute Remove-VMsnapshot cmdlet

  • Remove a particular checkpoint on a Virtual machine
Remove-VMSnapshot –VMName (Virtual machine name)
  • Remove entire checkpoint in your virtualization environment. This will search entire virtual machine and restore any checkpoint.
Remove-VMSnapshot –VMName *

Once remove the snapshot, the system will merge the checkpoint and remove the temporary avhd file without turn off your virtual machine.


  • Above scenario is applicable for Windows Server 2012 Hyper-V and Windows Server 2012 R2 Hyper-V.

Saturday, April 12, 2014

HeartBleed Bug on Virtualization Platform



Heartbleed Bug is a serious vulnerability in the popular OpenSSL. This weakness allows stealing the information protected, under normal condition by the SSL / TLS encryption used to secure the internet. For more info, please click here.

Next question:

Does your virtualization infrastructure vulnerable on HeartBleed Bug ?

This is what I have found out during searching to check if my infrastructure is affected.

Vmware Platform

Yes. Vmware has confirmed the following products are affected:-

  • ESXi 5.5
  • NSX-MH 4.x
  • NSX-V 6.0.x
  • NVP 3.x
  • vCenter Server 5.5
  • vFabric Web Server 5.0.x – 5.3.x
  • VMware Fusion 6.0.x
  • VMware Horizon Mirage Edge Gateway 4.4.x
  • VMware Horizon View 5.2 Feature Pack 2
  • VMware Horizon View 5.3 Feature Pack 1
  • VMware Horizon View Client for Android 2.1.x, 2.2.x, 2.3.x
  • VMware Horizon View Client for iOS 2.1.x, 2.2.x, 2.3.x
  • VMware Horizon View Client for Windows 2.3.x
  • VMware Horizon Workspace 1.0
  • VMware Horizon Workspace 1.5
  • VMware Horizon Workspace 1.8
  • VMware Horizon Workspace Client for Macintosh 1.5.1
  • VMware Horizon Workspace Client for Macintosh 1.5.2
  • VMware Horizon Workspace Client for Windows 1.5.1
  • VMware Horizon Workspace Client for Windows 1.5.2
  • VMware Horizon Workspace for Macintosh 1.8
  • VMware Horizon Workspace for Windows 1.8
  • VMware OVF Tool 3.5.0
  • VMware vCloud Automation Center (vCAC) 5.1.x
  • VMware vCloud Automation Center (vCAC) 5.2.x
  • VMware vCloud Networking and Security (vCNS) 5.1.3
  • VMware vCloud Networking and Security (vCNS) 5.5.1

Vmware has published about it here. Most Vmware products which with OpenSSL 1.0.1 are affected

Citrix Platform

At this moment, “No” for Citrix XenCenter and XenServer. But affected

  • Citrix Access Gateway
  • Citrix Netscaler
  • Citrix XenApp
  • Citrix Web Interface

Citrix has published about it here.

Microsoft Hyper-V Platform

No. Microsoft Hyper-V Platform does not use open-source cryptographic library (Open SSL).

Meanwhile, Microsoft Account and Microsoft Azure, along with most Microsoft Services, were not impacted by the OpenSSL vulnerability. Windows’ implementation of SSL/TLS was also not impacted.

For more detail, please click here.


If you’re environment are running the above platform and under affected list, please act fast to protect it before too late.

More details:-

Defrag Cluster Shared Volume in Hyper-V Host


Fragmentation is the most common word that we heard. How do you know when fragmentation has occur in your virtualization infrastructure. This often happened when your virtual machine performance start to degraded and occurred when using dynamic disk in production environment.

For fixed disk deployment in production environment, you won’t likely have this issue as the disk has pre-allocated earlier during provisioning.

Last time, we used to use “Repair-ClusterSharedVolume” cmdlet to defrag CSV. But this cmdlet has deprecated. Now it is recommended to run using the command “defrag”

defrag (csv mount point name)
defrag C:\ClusterStorage\Volume1

To check your disk fragmentation status, run

defrag C:\ClusterStorage\Volume1 /A /U /V

  • /A = Perform analysis
  • /U =print progress on the screen
  • /V = print verbose output

Below is the sample of two volumes that we are going to run defrag and check for fragmentation.

Volume 1

Displayed a result indicated that volume 1, do not require to defrag. So no fragmentation issue.


Volume 2

But volume 2 indicated that got fragmentation and we need to defrag the mount point.


To defrag the mount point we need to turn on redirect access first. Go to Powershell and execute command Suspend-ClusterResource.

About Suspend-ClusterResource Help:-


Suspend-ClusterResource (Cluster disk name) –RedirectedAccess


Begin to solve fragmentation by run defrag command after set disk to redirect access mode
defrag C:\ClusterStorage\CSV2


This process will run for quite a long period depend on how much your fragmented disk . Just wait till it complete.

While performing this operation, your production virtual machine is still up and running. However we still recommend that you run during non peak period as it will slightly impact your VM performance and this is similar when you performing VM backup using DPM.

End result:- Total fragmented =0


Once the defrag process has completed, you need to turn off redirect access by using this command

Resume-ClusterResource (cluster disk name)
Result-ClusterResource CSV2


Now your have solved your fragmentation issue, virtual machine should run in top condition.

Lastly before we sign off, do choose wisely on when to use dynamic disk and plan carefully your deployment to avoid fragmentation,

Wednesday, April 9, 2014

Starwinds News:- April 9, 2014


Some information sharing from our blog sponsor-Starwinds and free NFR to grab

News 1: – Shortlisted in DataCentre Solution Awards

StarWind iSCSI SAN&NAS and StarWind Native SAN for Hyper-V, have been shortlisted in the Datacentre Solutions Awards as the Datacentre ICT Storage Software of the Year.
Their Press Release is here:

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If you believe we deserve to win these awards please vote for us!

Thank you for your time and support!
StarWind Team

News 2 :- Free NFR Key for Starwind SAN V8 is available for IT certified professional

If you do have the following certification,


You can get free license is necessary to register here:

Hurry ! Offer is valid till March 31 2014.