— Virtual and software defined stuff. And more! —

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Have you had a “fling” lately?

If you aren´t familiar with the flings from VMware Labs, now is the time to get to now them. Flings are a bunch of handy Tools, built by VMware engineers, that could make your life easier working with with virtual Environments.

Here´s a few of my personal favorites:

VCS to VCVA converter
A migration tool from Windows based vCenter servers to the Linux based virtual appliance.

ESXtopNGC Plugin
An enhanced plugin-version of ESXtop for the vCenter Web Client.

 PowerCLI Cmdlet for NFS

Check them all out at

Just keep in mind, they are provided “as is”, without any kind of support, so try them out in your test environments first.


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Do NOT overprovision your virtual machines

It can never be said enough! Don´t overprovision your VMs. There, I said it again.
Overprovisioned VMs is probably the most common problem in vSphere Environments around the globe and, sadly, the business application industry still haven´t grasped this and continues to demand monster VMs in order to support their Products.

But there comes a time when you are forced to troubleshoot performance in your Environment, although your expensive, state of the art datacenter, was designed to run for years to come. Suddenly you´re running out of Resources in your cluster(s).

To prevent this form happening a few golden rules can come in handy.

Enable hot-add

Make sure you have enabled the hot-add feature for vCPU and vRAM on your VMs. This can only be done when the virtual machine is powered off but it´s better to Power it off once than every time you want to change Resources. Windows Server 2008 and newer supports both these features. See VMware kb 2051989 for a complete support matrix.

vRAM is better

Always try more vRAM Before adding extra vCPUs. Basically the same rule that has been used for many years now to speed up physical Windows computers.

Easy on the vCPUs

More vCPUs can improve perfomance but only up to a Point. The CPU Scheduler in your hypervisor has to Schedule the instructions from your vCPUs at the same time, More vCPUs makes it harder for your hypervisor to do this.


So how do I respond to my suppliers demands? The answer is, you don´t. Instead suggest a compromise that you start on a “reasonable” level and add more vCPUs and vRAM if and when it´s really needed.

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Unmount datastore from all hosts without scripting

VMware_iconDo you want to remove (unmount) a datastore from all hosts in your VMware vSphere Environment without scripting or fixing all your hosts manually (and slowly)?
Start your vSphere Client and switch to the Datastores and Data clusters view. Expand the tree and find the datastore. Right click it and choose Delete and boom, this dialogue shows where you can select which hosts you want to remove the datastore from.


I´m almost embarassed that I haven´t seen this function earlier but it´s there (in vSphere 5.5 anyway) and it´s really neat.


Unfortunately, if you want to add datastores you have to do it host by host so now is the time to browse your script folder. Or you can use this one. Copy to a text file, name it something like “add_datastores.ps1” and run through powercli.


Connect-VIServer your_vcenter

$vmhosts = Get-VMHost -Location your_cluster

foreach ($vmhost in $vmhosts)


New-Datastore -VMHost $vmhosts -NFS -Name datastore_name -Path “/vol/volume/qtree” -NfsHost x.x.x.x



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Clustering SQL Server 2012 on VMware vSphere – Planning

Clustering your SQL Servers can increase availablity for your databases but, first of all, it let´s you perform maintenance on your SQL Server without downtime. Database servers have a lot of dependencies and can be really tough to reboot in a production Environment. If you also have two VMware clusters running on separate hardware then you´re a few steps closer to full redundancy.

I´m currently working on a clustering solution on behalf of a client. Two virtual Windows Server 2012 R2 nodes with SQL Server 2012 on top of vSphere 5.5 and with shared iSCSI-storage on Netapp.

Clustering in a virtual environment is fully supported by Microsoft and VMware. Great! Then I found this kb article on the VMware knowledge base where you can find out the real truth. What do you know, DRS and vMotion is NOT supported. Everything will work as expected except that you won´t be able to move your VMs around between host.


Other things I have stumbled upon

  • The paravirtual SCSI adapter (PVSCSI) is not supported in a Microsoft Failover Cluster (MFCS)
  • Use separate disk controllers for your local drives.
  • You cannot use Managed Service Accounts (MSAs or GMSAs) in a cluster.
  • TempDb is now supported to run on local disk because it is flushed every time you restart the SQL Server service.
  • Use mount Points instead of drive letters. Best practice is to create a separate disk that holds all of your mount Points and it doesnt have to be big. However, it must be over 3 Gb if one of the mount Points is were you will install the SQL binaries. The installer checks free space on the root disk and can´t see that your mounted disks, one step down in the tree structure, is large enough. I read in Microsofts documentation that mount Points are totally transparent. No, not really!
  • Manage your shared disks through SnapDrive. ALWAYS! Do not remove disks in Failover Cluster Manager. If you do, you can look forward to a few extra hours of disk removal, cleaning up LUN mappings and starting over from the beginning with adding your disks (speaking from experience here).
  • Sometimes the SQL Server installer can´t move your cluster disks to the SQL Server cluster role and stops with an error message and an incomplete installation. This requires an uninstall and a reboot of the Windows node your working on Before you are back on track. Create a new cluster role and choose “create empty role”. Rename it to “SQL Server (MSSQLSERVER)” which is the default name the installer would suggest. Now you can move your disks to the new role and next time you run the installer it will detect this and skip this part.
    Read more in this article by Chandra550 (many thanks)


To be continued…