Extending capacity of a virtual disk on MD3200i !!

We have a client who has got several ESXi servers. Recently, a local drive on one of the virtual servers reported low disk space. I need to extend the space of this drive at any cost.

This local drive is actually allocated from a virtual disk on the SAN device they have, which is Dell MD3200i. This particular virtual disk resides on a Disk Group created from a RAID 6 volume as well. The LUN or virtual disk we are talking about is mapped to the VMware host which in turn is mounted as a hard disk on the virtual machine.

So, in order to extend the drive capacity the procedure will be as follows :

  • Increase the capacity of the virtual disk on MD3200i:  Steps are shown below:-

Connect to the Dell MD3200i console.


Select the tab Storage & Copy Services. Right click the virtual disk under the respective Disk Group, and select Increase Capacity.



Click on OK, when the below window appears:


Now, you will have to input the amount of space you need to extend and click OK.


The process will begin and you will find a status bar as shown below:


Even though we are increasing the capacity of a single LUN in a disk group, all other LUNs will be prepared and defragmented which will further increase the time for the entire process.


The above image shows the status of the task. Wait till the capacity of the lun is increased.

  • Extend the datastore capacity in ESXi host:

You have increased the capacity of the lun at this point. As informed earlier, the lun is mapped on the host server. The datastore size should change in the ESXi server as well.. right ??? Even-though you refresh your storage, the capacity of the datastore in the ESXi host may not change. At that time you have to manually extend the datastore capacity.

First, log in to the ESXi host server. Navigate to Configuration -> Storage, and select your datastore [as well as virtual disk]. Select the datastore and click on Properties.


Click on the Increase button as shown below:


Next, it will show you the current LUN space and the free space available [free space obtained from increasing lun capacity]. Click Next.


In the next step, it will combine both the free space to the lun. Click Next and then Finish.


Now you have completed the steps for extending the datastore.

  • Extend the hard disk from the virtual machine Edit Settings:

On the ESXi host, select the virtual machine and click on Edit Settings. In order to extend the capacity of the hard disk the virtual machine should be in shutdown state as we know. Select the hard disk and increase the capacity as required. Once done click on OK.



Turn on the virtual machine and log in to the server.

  • Extend the capacity of the drive from Disk Management

This is the final step in the task. Once logged in to the server, launch Disk Management. Select the disk. You will notice unallocated space on the right hand side of the disk. Right click the partition and select Extend Volume.


Resolve “Critical Structure Corruption” error on Windows Server 2012 & Windows 8 OS !!

I recently happen to come across this issue after the restore of a Windows Server 2012 Standard server from one VMware ESXi server to another, using Veeam Backup & Replication. The Windows server started to reboot intermittently with the error “Critical Structure Corruption” in the VM console. A reboot will be required hence to successfully log in backup to the server.

Below is a screen shot of a similar issue :


Once, I got access to the server the first thing I checked was the event logs. Under the System logs, I noticed a critical error as shown below :


A quick search on the event ID and the corresponding error code made me understand that this is a common issue with Windows Server 2012 R2 and Windows 8.1 machines.

Common resolution steps are :

  • For ESXi versions 5.0, 914586 [ Update 2 ] issue can be resolved by an upgrade to Update 3
  • For a quick resolution, the workaround is to manually add a CPUID mask for the affected VMs as shown below :
  1. Power off the VM
  2. Right click the VM and select Edit Settings
  3. Click on the Options tab
  4. Select CPUID mask under Advanced tab
  5. Under the Register Column, locate the edx register under Level 80000001
  6. Paste the following in the value field and click OK twice



Reference : VMware KB [http://kb.vmware.com/selfservice/microsites/search.do?language=en_US&cmd=displayKC&externalId=2060019]