I recently encountered an interesting question, maybe not the one you will see every day. A vCenter Center server runs a large number of Clusters; the VMs on those clusters are controlled by a considerable number of DRS rules. The question that raised; “How do we know if the DRS rules we once designed are still in place?” In the course of time, rules can be disabled, VM or Host groups does not match any more. Trying to answer this question by going through the vCenter Server configuration is not the way to go.

Thankfully, the VMware PowerCLI contains a useful Cmdlet Get-DrsRule that enables you to create a dump of the configured rules for each cluster. This makes checking your configuration a lot easier.

But there is another thing, now we know about the configuration, but what do we know about the actual situation? For instance, VM to Host affinity has “should” and “must” rules, but to what extent is a “should” rule fulfilled?

So time to create a PowerShell script which performs the following tasks; for each Cluster within a vCenter Server, a dump of the configured DRS rule is made. The second part of the script determines on which host a VM is running and compares it to the configured rules. The script will also report if a DRS rule is disabled and displays the power state of each VM. You will probably worry less about a powered down VM.

The script can be found here on GitHub.

I am aware that the script and my programming skills are far from perfect, so expect updated versions in the future.

Install VMware Tools in CentOS 7


20160708-01The VMware Tools are an essential part during the installation of a Virtual Machine. For many Operating Systems you can go the easy way and install the VMware Tools right from the vSphere Web Client. You will install the VMware Tools that comes bundled with vSphere ESXi.

BTW, Since September 2015, there is also a downloadable version of VMware Tools (versions 10.0, 10.0.5, 10.0.8 and 10.0.9). The Downloadable versions (should be seen as a Solution) support all version of ESXi from 5.0 and later, see VMware Product Interoperability Matrixes. See the release notes of the latest version.

So far so good, for Windows Operating Systems, the installation of the VMware Tools is a no brainer. For Linux operating systems, installation is more complicated, for most reasons because Linux Operation Systems do have multiple options to install software.

In my case, I usually work with CentOS (based on the sources of Red Hat Enterprise Linux RHEL). CentOS uses RPM as a packet manager. Packet Managers do have many advantages while maintaining a Linux server. Unfortunately, the bundled version of the VMware Tools doesn’t come in .rpm format, but as an archive file in tar.gz format. Although installation of a .tar.gz is straightforward, it is not the way to go.

An alternative is using VMware’s OSP repository, see this nice post in case you want to know more. You can browse the OSP repository here. For CentOS, browse the corresponding RHEL version. You will also notice that there is no entry for RHEL7. Trying the RHEL6 version failed in my case.

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VM Storage Policies / Profiles, don’t mix up


With vSphere 5.5 came many, many changes. Without a doubt, the biggest change is the prominent role of the vSphere Web Client, now being the preferred client to manage your vSphere Clusters.

Being very familiar with the traditional vSphere Client, it takes a reasonable amount of time to get used to the vSphere Web Client (vWC). In my case, I always tried to perform the action with the vWC, with the traditional Client for Fall-back or while in a hurry.

While refreshing my knowledge about Storage Profiles, I noticed, in vSphere 5.5 “Storage Profiles” have been renamed to “Storage Policies”.
Although, not quite. Figure 1, shows part of the home screen of the same vCenter 5.5 server.


Figure 1– [Left] vSphere Web Client – [Right] traditional vSphere Client

But, soon I discovered that not only the name of this feature has changed.

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vOPS Server Explorer 6.3 release


Today, Dell released the latest version of the vOPS Server Explorer, version 6.3 to be more precise. Last year, Dell acquired vKernel and with that, its flagship product vOPS Server Standard.

vOPS Server Explorer is a freeware suite, this version adds two new utilities, Storage Explorer and Change Explorer, plus adds improvements to Environment Explorer. So there are now a total of five utilities in the vOPS free VM tool.

  • Environment Explorer
  • vScope Explorer
  • Search VM Explorer
  • Storage Explorer
  • Change Explorer

vOPS Server Explorer uses the same analytics and advisory engine from the paid vOPS Server Standard product, all five of these utilities provide virtual administrators with a rapid assessment of the state of their environment.

vOPS Explorer-01

Figure 1 – Storage Explorer (provided by Dell)

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Veni, vidi, VAAI


Veni, vidi, VAAI

Recently, I was asked to investigate a performance issue on a VMware environment. Configuration of the ESXI hosts and storage was just finished and engineers were busy deploying Virtual Machines from a Template. The main issue was; “Actual time to deploy a VM is much more than expected”.

The Environment consists of the following components:

  • Dell Equallogic PS4100X, with 24 x 300 GB 10K SAS drives in RAID-50 config;
  • Storage switches, two Dell PowerConnect 6224 stacked;
  • ESXi servers, three Dell R815, 32 GB and 6 NICs;
  • VMware vSphere 5 Enterprise Edition.


First step was to check the configuration of the components. Configuration of the servers and storage was according to Dell’s “Configuring VMware vSphere Software iSCSI with Dell EqualLogic PS Series Storage”.

At first glance, everything seems to be OK, so now it is time to do some testing and see with my own eyes what is going on. I started the deployment of a template of a VM, configured with a 60 GB virtual disk on the same ESXI server, at the same time logged in on the console and started esxtop and switched to the “disk adapter” view. During the deployment, the iSCSI software adapter (vmhba40) showed a steady 60 MB/s read (MBREAS/s) and 60 MB/s write (MBWRTN/s). The Total Latency (GAVG/cmd) is 4.10 ms., which is fine (as Mr. Eric Sloof explained in an Advanced Troubleshooting presentation).

The total time for this deployment was at least 15 minutes.

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Resizing Virtual disks and some annoyances


Increasing the size of a virtual disk is a routine job, especially in a Windows environment. Since Virtual Infrastructure 3.5, the Client offers the ability to adjust the size of a Disk File. But sometimes, there are some annoyances.

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