vCenter Server for Windows and vCSA compared

The most glaring difference, as the name implies, is that vCenter Server for Windows will only run on a Microsoft Server operating system.. On the other hand, vCSA is a SuSe Linux Enterprise Server 64-bit based appliance which comes lock, stock and barrel ready for importation.

The second important difference is related to vSphere Update Manager (VUM) which, as you probably know, can be installed alongside on the same server running vCenter Server for Windows. Unfortunately the same does not apply to vCSA meaning that you’d still be needing a Windows box if your plans include deploying VUM. My prediction is that vCSA – VUM integration will be made available a couple of updates down the line. Failing that, it will be addressed in the next major release.

Thirdly, your database options are limited to the following:

• vCenter Server for Windows – you can either install the bundled PostgreSQL database for environments with no more than 20 hosts and 200 virtual machines or in the case of larger environments, use a Microsoft SQL or Oracle DBMS.
• vCSA – The bundled PostgreSQL database which now supports environments of up to 1000 hosts and 10,000 virtual machines. This will probably suffice for most scenarios but if need be, you can still use an external Oracle DBMS.

Similarities between vCenter Server for Windows and vCSA

• The hardware requirements are identical to both. Figure 1, reproduced from VMware’s documentation, specifies the minimum CPU and Memory requirements according to the environment size.

Figure 1 – vCenter Server Minimum Hardware Requirements

• Both can be managed with the traditional vSphere or web based client. In the case of vCSA you can also SSH to it or use the Direct Console User Interface to change stuff such as the root password and network settings (pretty much like you would do on an ESXi host). With the release of vCenter Server 6.0 Update 1 it is now possible to administer vCSA using the newly released HTML 5 based Appliance Management User Interface. One great feature is the ability to patch / upgrade vCSA using an ISO image or URL based patching.

Figure 2 – Appliance Management User Interface

• At last, and I emphasize this as in the past vCSA presented some serious scalability limitations preventing a more thorough uptake, both flavors enjoy the same set of scalability metrics. These are listed by way of Figure 3 reproduced from the “What’s New in the VMware vSphere 6.0 Platform” whitepaper.

Figure 3 – vCenter Server Scalability Numbers

Weighing advantages and disadvantages

vCSA Pros

• Quicker to deploy since everything is preconfigured and you don’t need to install anything apart from running the actual installer, supplying a couple of details and sipping tea as you sit back watching it do its thing.
• The bundled database is scalable enough to cater for most environments unless of course you’re planning on deploying 1000+ hosts and/or 10000+ vms.
• You do not need separate licenses for Microsoft Windows Server so overall this might turn out to be a cheaper option.
• From a security perspective, vCSA traditionally presents a smaller attack surface since it runs on Linux though it should be said that Microsoft have upped their ante considerably in this department.

vCSA Cons

• As with many appliances vCSA is somewhat of a black-box. You’ll be needing some intermediate Linux skills when troubleshooting or VMware support when things go dark.
• You still need to have a separate Windows box on which to install and run VUM.

vCenter Server for Windows Pros

• In my opinion it’s easier to troubleshoot vCenter Server for Windows if anything due to a larger user-base and the fact that fixing Windows related issues is generally easier, from my experience at least.
• VUM can be happily installed on the same server running vCenter so you don’t need to worry about managing two servers.

vCenter Server for Windows Cons

• For larger environments, you’ll definitely be needing an external database meaning more license and hardware related costs.
• While deployment is still easy, it definitely takes longer to install and configure vCenter Server for Windows.

Conclusion

The bottom line is that VMware is seemingly moving towards relegating vCenter Server for Windows to history. This is evident with the features that come with version 6 and the recently released Update 1. It’s only a matter of time before VMware completely close any functionality and feature gaps that remain between the two flavors. If they can address the VUM co-existence issue, I’m pretty sure more people would opt for vCSA without as much as giving it a second thought.