vCenter Server for Windows and vCSA compared

UPDATE: This post has been updated (20-July-2017) to reflect the changes in vSphere 6.5



This post highlights the similarities and differences between vCenter Server for Windows and vCenter Server Appliance (vCSA) for both vSphere 6.0 and 6.5. I’ll also touch briefly on the features common to both and those exclusive to vCSA 6.5 as well as the pros and cons of going for a specific version.


Differences and Similarities

Base Operating System

The most glaring difference, as implied by its name, is that vCenter Server for Windows runs exclusively on a Microsoft Windows server operating system. My article shows you how to install it. The appliance version (vCSA), on the other hand, is based on SUSE Linux Enterprise Server 64-bit and comes as an OVF appliance lock, stock and barrel ready for use. I covered the installation of vCSA 6.0 here and vCSA 6.5 here.

UPDATE: vCSA 6.5 now runs on VMware’s propriety Photon OS and not on SUSE Linux.


Database Options

There’s a difference in terms of the database options available when installing vCenter Server especially in terms of scalability. This equally applies to both vSphere versions 6.0 and 6.5.

  • vCenter Server for Windows: For environments with no more than 20 hosts and 200 virtual machines, use the bundled PostgreSQL database. In case of larger environments, use a Microsoft SQL or Oracle DBMS for better scalability and performance.
  • vCSA: The bundled PostgreSQL database now supports environments of up to 1000 hosts and 10,000 virtual machines which will suffice in most cases. You still have the option to use an external Oracle DBMS if you want better performance and scalability.


vSphere Update Manager (VUM)

If you have vCenter Server for Windows deployed, you probably know that VUM can be installed on the same server as vCenter. The same is not true for vCSA 6.0 as a separate Windows box is required if you want VUM deployed to your environment. My prediction is that VUM will be embedded in vCSA a couple of vSphere updates down the line. If not, it will be addressed in the next major release of vSphere.

IMPORTANT UPDATE: As predicted, VUM is now embedded in vCSA 6.5! You no longer need to install a separate Windows box.


Hardware Requirements

The hardware requirements are identical irrespective of vCenter Server flavor and vSphere version. Figure 1, reproduced from VMware’s documentation, depicts the minimum hardware requirements per type of deployment and environment size.

Figure 1 – vCenter Server hardware requirements

Figure 1 – vCenter Server hardware requirements


vSphere Clients

Both flavors of vCenter 6.0 can be managed using the thick (C#) client or the vSphere Web Client. Note, however, that you can no longer manage vCenter Server 6.5 using the thick client.

With the appliance version (vCSA), you can also SSH or use the Direct Console User Interface (DCUI) for administration purposes. Additionally, if you upgraded to vCenter 6.0 Update 1, you can use the HTML 5 based client instead of vSphere Web client. However, bare in mind that it does not provide all the latter’s client functionality.

Also available since vCenter 6.0 Update 1, the Appliance Management client (https://<vCSA IP address or host name>:5480) can be used to configure settings related to networking, access and more. One pretty nifty feature is the ability to patch or upgrade the appliance via ISO or URL based patching as shown in Fig. 2.

Figure 2 - The vCSA Appliance Management tool can be used to upgrade the appliance

Figure 2 – The vCSA Appliance Management tool can be used to upgrade the appliance


Scalability and Feature Parity

In the past, vCSA presented some serious scalability issues that held it back from being deployed to production environments. With vSphere 6.0, both vCenter Server versions enjoy the same set of scalability metrics and features as listed in Fig. 3 kindly reproduced from the What’s New in the VMware vSphere 6.0 Platform whitepaper.

Figure 3 – vCenter Server scalability metrics

Figure 3 – vCenter Server 6.0 scalability metrics


This is no longer the case with vSphere 6.5 which is set to be a game changer in terms of which version of vCenter Server to deploy. Simply put, vCSA 6.5 is superior in terms of the features offered and is the VMware recommended way forward.


New features exclusive to vCSA 6.5

As I just mentioned, vCSA 6.5 offers features not available in vCenter Server for Windows 6.5. I cover these features in my Say Hello to vSphere 6.5 post. To reiterate, here are the main ones. I’ve also included links to posts I’ve written on each.

1 – Native UI Installer and Migration Tool

2- Native vCenter High Availability

3 – File-Based backup/restore


Deciding on the flavor of vCenter to go for!

vCenter Server Appliance


  • Quicker to deploy since vCenter is readily configured. Simply run the installer and supply a few details. Compare this to setting up a physical server or VM, installing Windows, etc.
  • Less hardware (and costs) since vCSA runs exclusively as a VM (OVF appliance)
  • The embedded PostgreSQL database is sufficiently scalable and robust to cater for most environments; 1000 hosts and 10000 VMs.
  • No need for extra MS licenses. Even better with vCSA 6.5 since VUM is embedded meaning no need for a separate Windows box. Overall, a cheaper option.
  • Intrinsically more secure since it presents a smaller attack surface as vCSA 6.0 and 6.5 run on SUSE Linux and Photon OS respectively.

vCSA Cons

  • vCSA can be somewhat of a black-box if your Linux skills are not up to scratch.
  • With vCSA 6.0, you need a separate Windows box to run VUM. This is no longer the case with vCSA 6.5.


vCenter Server for Windows


  • Easier to troubleshoot, if anything, due to a larger user base and because fixing Windows related issues is generally simpler, from my experience at least.
  • VUM can be happily be installed on the same server running vCenter so you don’t need to worry about managing two servers. This only applies to vSphere 6.0.


  • For larger environments, you need an external database meaning more license and hardware related costs.
  • If you go physical, more hardware needed, more costs.
  • More prone to security issues due to the underlying OS which necessitates of regular patching and on the OS being a popular attack target.
  • Deployment may be easy but it definitely takes longer to install and configure.


Verdict: I would personally go for vCSA 6.5 not only because it is recommended by VMware but also because of the extra features offered. If you’re Linux shy or the type who’d rather wait for one or two major updates before taking the plunge, then stick with vCenter Server for Windows 6.0. You can always use the migration tool to move to vCSA 6.5 at a later stage should you change your mind.



The bottom line is that VMware are moving towards relegating vCenter Server for Windows to the history books of virtualization. This is evident since the release of vSphere 6.0 with both vCenter flavors having identical feature parity and, lately, vSphere 6.5 with vCSA taking the lead. It’s only natural to assume then, it’s only a matter of time before VMware drops the vCenter Windows version altogether.

Finally, here are a few more links if you wish to dive in deeper.


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26 thoughts on "vCenter Server for Windows and vCSA compared"

  • vBlackCat says:

    Hi jason,

    I know I may be a little late but if you still keep an eye on this post, could you please clarify something for me ? (and forgive me if I missed something and the question is stupid)

    You wrote that the PostgreSQL database bundled with the VCSA can be replaced by an external database, should we need to scale up beyond 1000 hosts and 10.000 VMs. But it is in fact the maximum hosts and VMs that can be handled by vCenter 6. So did I miss something ? In which precise scenario could you really need to join the VCSA to an external database ?

    Best Regards,

    • Jason Fenech says:

      Hi there,

      There’s no such thing as a stupid question! You’re right in that according to VMware, the VPostsgres database will scale out to support the maximum number of hosts and vm possible i.e. 1000 and 10000 respectively. Even if in truth, I don’t have any insight on how the database would perform if these maxima were ever reached, I believe performance could be an issue which could be one reason why you would want to put the database on db dedicated servers.

      The largest environment I ever worked with, comprised roughly of 50-60 ESXi hosts and approx. 5000 vms. Again speaking from experience, at my previous workplace we always decoupled the vCenter Server database from the vCenter Server itself by offloading it to an MS SQL cluster. We did this for disaster recovery and redundancy purposes given that the database is the single most important component. What this achieves, is the ability to have a freshly installed vCenter Server reconnected to the last known good instance of the database when things go haywire. This comes as an add-on to having backups of both the vCenter Server and the database of course.

      Also, in large companies you may have a dedicated DB team with management wanting them to manage VMware databases so again this might be a use-case calling for separating the db from the vCenter Server.

      However for most SMBs, a lock, stock and barrel vCenter Server (windows or vsca) should suffice provided of course you’re backing it up on a daily basis.

      Hope this helps.



  • Peter P says:

    If you go the appliance route, is backing up the vCenter db just a case of creating an ovf of the appliance? Or is that not possible/efficent?

    • Jason Fenech says:

      Hi Peter,

      Actually I have a pending post on the subject matter. Hopefully it will be published soon. To be honest, I never really tried backing up VCSA using the OVF method since this entails powering down the vm first which is generally something you’d probably want to avoid.

      This KB has all the details on how to backup / restore the vPostgreSQL database.



  • Ahmed123 says:

    Hi Jason,
    The article is informative and had few clarifications
    1. We are running single instance of vCenter 6.0 with PotsgreSQL and would like to know, How easy is it to migrate to vCSA 6.0 ? We are planning to install SRM and there is a limitation of 20 hosts and 200 VM on PotsgreSQL. So though of looking at vCSA 6.0
    2. Does vCSA support HA?
    3. If suppose I go with vCenter 6.0 windows server( VM) with embedded PSC for primary site what is the best design, like to have two vCenter instance OR SQL 2014 Cluster with single vCenter instance which will be part of HA/DRS cluster. Read your article and like to mention we have dedicated DBA to handle SQL backups.
    Thanks in advance

    • Jason Fenech says:


      Thank you for the comment.

      1. Easy is subjective since the probability of something going wrong during the migration, increases the more complex your environment gets. Sometimes it’s best to install VCSA from scratch and just add the hosts to it. You will lose things like DVS, host profiles, the resource pool hierarchy if DRS is enabled, etc. VMware do provide a migration tool but as far as I know you can only migrate from vCenter Server 5.5 for Win to VCSA. You can also try backing up the postgres DB and restoring it to a freshly installed VCSA as per this

      2. Yes, VCSA 6.0 fully supports HA (see link). VCSA 6.5 is even better as it provides native HA.

      3. Again, it all depends on your needs, workload, whether the nodes are in the same DC or geographically dispersed, etc. This white paper should help. This is my opinion, but if you’re in no rush I’d wait until U1 for vCSA 6.5 is released since it offers much more in terms of HA, backups, etc.

      Hope this helps.


      • Jason Fenech says:

        For completeness sake I need to add that the embedded migration tool in the VCSA 6.5 installer, does in fact allow you to migrate from vCenter Server for windows 5.5 or 6.0.

        “This installer allows you to migrate vCenter Server (5.5 or 6.0) for Windows, vCenter SSO 5.5, or Platform Services Controller Appliance 6.0, to version 6.5.”

  • Ahmed123 says:

    Thanks Jason.

  • Bojan Zivkovic says:

    Hi Jason, excellent article. Having worked with MS technologies I started to learn Linux (RHEL 7/CentOS 7). Is knowledge I am going to have after a year or two will be sufficient to successfully manage Linux deep inside vCSA – so far I have been PowerCLI fan? Honestly I do not have a clue what is a difference between RHEL and SUSE, let alone Photon OS I have never heard of until today.


    • Jason Fenech says:

      Hi Bojan,

      Thank you for your comment. Like you, I lean more on the Microsoft side of things than Linux, but I am sufficiently versed with Linux to know my way around most of the time. You should be good to go with a year or two of basic to intermediate Linux experience under your belt. That said, most of the time, you’ll be using basic commands common to all Linux OSes and distros including Photon. PowerCLI is great to know, so kudos to you. SUSE is actually based on Redhat if I’m not mistaken. Photon is a VMware propriety OS which is described as being a minimal Linux container host designed for performance. You can read about Photon here.



  • Lukasz Karbownik says:

    Hi Jason
    Great info, maybe you can sort out my doubts migrating to vCSA.
    We are on 5.5 version with Windows Vcenter server and separate MSSQL database. We utilize SRM and EMC RecoveryPoint solution.
    My team is not linux literate and 95% of our machines run on windows servers.
    Would you still recommend implementing appliance or stick to vCenter Server for Windows with that set up and migration task in mind.
    Thank You

    • Jason Fenech says:


      The short answer is that VMware will be dropping vCenter Server for Windows as recently announced here. This means that vCSA will be the one and only option in the future unless VMware reverse direction.

      The long answer is that vCSA 6.5 gives you an embedded VUM, in-built database, native HA, etc. You also save on MS licensing by ditching MS-SQL. SRM 6.5 is compatible with vSphere 6.5. I don’t know much about EMC Recovery Point but you can have a look at the compatibility matrix. Migrating to vCSA is the recommended option but you obviously need to factor in the complexity of your environment and plan accordingly. As regards Linux, you should rarely need to work from shell. Even then, from experience at least, it’s mostly basic Linux commands and VMware command-line tools you’d be working with.

      Hope this helps.


  • Vijay says:

    Hi Jason,

    I do not see an option to use an external Database with VCSA 6.5. I think it is embedded only model in VCSA 6.5. Please clarify.


    • Jason Fenech says:


      Correct. vCSA 6.5 does not support any external databases. However, vCSA 6.0 supports external Oracle databases. The documentation is a bit lacking in this regard.



  • Sid says:

    Hi there
    I have an ESXi server with a windows 2k12 R2 server VM and an RHEL 7 VM with different ip’s
    Will I need to install VCSA for the RHEL as well as the vCenter for windows in order to progress
    I am a novice in this field and trying to learn so please don’t mind if it appears that I am not making any sense.

    • Jason Fenech says:

      No. That’s not how it works. You just need to choose which vCenter version to use. I’d suggest going for vCSA. The OS installed on the VMs does not play any part in choosing the vCenter type.

  • Darren says:

    I know this post was made two years ago, so I am not sure if you will see this. I am pretty new to vSphere as a whole, I managed to get the ESXi and vCenter up and running but I went with vCenter for Windows rather than the vCSA as I was unaware how much better vCSA is at the time. While I am definitely going to migrate to vCSA, my question is on setting up vCSA itself.

    I have downloaded the most recent version of the vCSA 6.7.0, which now comes as an ISO rather than an OVA file. I know I can deploy the vCSA as a VM to the ESXi hosts, and while I won’t have a lot of ESXi hosts in my environment it seems odd that you would have to do this for multiple host.

    Could I not just install the vCSA locally on my Windows Server machine then just add the ESXi hosts through the Web Client, which is what I did for vCenter for Windows version? For example if you have 10 or more ESXi hosts to manage to, it seems silly that you would have to put vCSA as a VM on each ESXi host, that seems super repetitive.

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