VMware vCenter Server - Physical vs. Virtual

This post is coming straight out of discussions I had with a client about, "How a vCenter Server should be deployed?". Since vCenter manages a virtual infrastructure you can either install it on a physical x86 server or as a Virtual Machine.

vCenter is an important machine and I have written about the importance of Protecting the VMware vCenter Server in one of my articles - Providing Protection & High Availability to a VMware vCenter Server. I would recommend you read this in order to understand the importance of taking the decision of keeping your vCenter Physical or Virtual.

People often ask me this question not only for vCenter but for all the other applications which they want to Virtualize. My answer to them is usually this "PLEASE ASK THE APPLICATION VENDOR". The team and the organization who have developed the application know the best about the attributes of the application hence they should be able to tell you whether an application can be virtualized or not.

vCenter being a VMware application, let's see what VMware has to say about Virtualizing the vCenter Server. As per page number 2 on the following white paper, VMware says - "Users can run vCenter Server in a virtual machine or on a physical server. We recommend running vCenter inside a virtual machine."

Sweeeett.. I believe the recommendation is exactly inline with my thought process... If you cannot Virtualize your own application (the vCenter Server) which is CRITICAL for a Virtual Infrastructure, you cannot really ask the application owners to Virtualize their critical apps on the VMware vSphere platform... Hence this is a great point which IT today can take to their application owners and convince them to Virtualize whatever fits on a VMware virtual machine today (I guess everything with vSphere 5.1. Read What's New - 5.1 to know more...)

Great, apart from the story of "Eating your own Dogfood", let's look at some other reasons which would help us take this decision around virtualizing vCenter or NOT.....

Well the above points are just a snapshot of what I think and I believe these pointers give you good enough reasons to decide whether your vCenter should be Virtual or Physical. 

I remember someone asking me a question which was "What will happen if the Virtual Machine which is running the vCenter goes down due to an ESXi server failure??"

The answer is that VMware HA will still work since it does not require vCenter to be up and running.. So if you have a HA cluster, you can be sure that you will get back the control on your environment as soon as the vCenter Virtual Machine is up on any other host in the cluster with the help of HA. 

What will happen if your PHYSICAL vCenter Server goes down??? I will leave you with this thought for now... :-)

Yup, Virtual is Better for me....

Hope this helps you take a decision on what is best for your environment..... Do share your thoughts if any!!

Providing Protection & High Availability to a VMware vCenter Server..

vCenter being the heart of a virtual infrastructure can be considered as one of the most important piece of the puzzle. I have had numerous discussions with customers, colleagues and VMware partners about the importance of vCenter Availability and the options to protect the vCenter to improve the up-time and mitigate any risks around losing the control of your Virtual Infrastructure.

This article is to ensure that we document all the available scenarios and options and help others to take decisions around improving the availability of VMware vCenter. I am sure there would still be some scenarios out there which I might have missed, and would be happy to discuss them through the "Comments" section of this post.... So feel free to share your thoughts!!!

Alright let's begin.....

First of all lets start with a few basic questions to clear the fog around the role of VMware vCenter Server (I am doing this for the new kids on the block..)

What is vCenter Server?

Virtual Center provides a centralized and extensible platform for managing virtual infrastructure. VMware vCenter Server, formerly VMware VirtualCenter, manages VMware vSphere environments allowing IT administrators simple and automated control over the virtual environment to deliver infrastructure with confidence. More Details can be found here.

vCenter Should be Virtual or Physical?

Yes your vCenter is an application which can be installed on Virtual Machine as well.. Read my post on this topic - VMware vCenter Server - Physical vs. Virtual. This should tell you what is the best option for your environment.

vCenter Server (Windows Based) or vCenter Server Appliance a.k.a VCSA (Linux Based)?

For Linux lovers vCenter is not restricted to Windows anymore, you can also get a Linux based appliance from VMware. I have written a post about "Choosing the Platform for your Virtual Center. vCenter Server Appliance(vCSA-Linux) vs vCenter (Windows)"!! I would recommend you read this to understand which is a better option for your environment.


Whether its Physical or Virtual, Linux Based Appliance or Windows Based, it is important that we protect the virtual center so that we do not lose control of the ESXi servers and the virtual machines which run the business applications. Let us quickly look at the options to protect both vCenter Server (Windows Based) & vCenter Server Appliance a.k.a VCSA (Linux Based)...

Great, so now we have the methods available in the table... Lets dissect them one at a time to see what each option has to offer.

Option 1 - Use VMware vSphere HA  - If your vCenter is a Virtual Machine you can place the vCenter Virtual Machine in the VMware HA cluster. HA will protect the vCenter Virtual machine just like any other virtual machine. If the ESXi server which is running the vCenter VM goes down, HA will kick-in and power on this VM from the shared storage, on another HA cluster member host. The only downtime in this case would be the time taken to reboot the vCenter VM. Pretty cool, right!! I appreciate this from VMware...

Option 2 - Cold/Standby vCenter - This is a poor man's HA and I have seen customer's use this configuration, especially the one who have the vCenter as a physical server and cannot use vSphere HA. The  architecture of this deployment, needs you to have a remote database for vCenter application. You have 2 servers with same version of vCenter application installed. In case the first one goes down, you power on the other server which connects to the same database and hence pulls up all the configuration. This method surely works but needs human intervention. Hence if you vCenter goes down in the middle of the night when your backups are happening using VADP, your backups would fail and you would not be able to fix this unless you come back in the morning and see the damage......


Option 3 - Using vCenter Heartbeat - vCenter Heartbeat is a high availability solution for vCenter Server which protects the vCenter against OS, Application, Database(SQL), Configuration, Networking or Hardware failures. Yup it also protects the SQL database and can be installed across sites as well (remote location). The beauty is that if you have a Heartbeat license, you would only need one vCenter license for both Primary and Failover site. You should be able to get more information about Heartbeat on the following link.

The reason I have highlighted this option in the above table is due to a reason. Heartbeat comes with a cost and I would highly recommend this option for environments where vCenter up-time is critical. Environments with VMware View, VMware vCloud Director or wherever vCenter APIs are used, the availability of vCenter Server defines the availability of these services. Hence if these services are important vCenter should be given protection using vCenter Heartbeat.

Option 4 - Third party Solutions to Protect vCenter Server - There are a number of options available to name some, configure MSCS for vCenter windows based server, Neverfail etc. can help you protect vCenter Server.

Since, vCenter needs a minimum of 2 vCPU's we cannot use VMware FT to protect this virtual machine. However, I am sure VMware would look at supporting VMware FT with SMP (symmetric multi-processing), which would give another option to customers to protect vCenter Server and ensure they have full control and manageability for their VMware Virtual Environments.

Feel free to share your thoughts around this topic and I hope this helps you design your vCenter with the best suited options for your VMware environments.