Hi all,
A very generic title, I know. I'm asking your opinion / vision on the design and implementation of the vCenter server. Currently I am studying for the VCAP-DCD certification and in this certification journey, every design choice must be well thought through. One of the items discussed was the choice of the vCenter server. In short, you have 2 options:
- Windows based vCenter server installed manually on top of a Windows OS.
- Linux based vCenter server, which comes as a virtual appliance.
Since the limitations of the VCSA in 5.5 have been raised 100 hosts and 3000 virtual machines, it is a suitable candidate for smaller to medium infrastructures. Both variants have options for either a local (DB2 for the appliance and MSSQL for the Windows version) or remote database. Remote databases have advantages such as usage of the existing MSSQL or Oracle environment (if available), separation of duties, and perhaps the vSphere administrator is not really strong in the SQL field.
Local databases have advantages such as the all in one package that you have with vCenter, with dependencies only local to the system. Using the existing MSSQL or Oracle environment can also be a weakness in the design choice. Outages on the production platform (which could host SQL) would result in the outage of the vCenter server, and therefore a part of the management tools of the vSphere platform.
The Windows based platform can also be installed on either physical hardware, or as a virtual machine. Physical hardware has the advantage that there is no dependency on the virtual infrastructure resources to perform management of the virtual environment. Disadvantages of using physical hardware for the vCenter server is that extra hardware is necessary, dedicated for the vCenter server. You cannot take advantage of snapshots, or move easily to another host if you wish it so.
Because each environment is unique, and there is no one size fits all solution, I would like to ask you all to share some thoughts about the design, and the implementation of vCenter as a service in the virtual infrastructure.
In my implementations of the vCenter server, I've used both. On smaller infrastructures (max 10 hosts or so), I went with the appliance for the all in one advantage, and mainly because the customer had to buy a Windows license for the vCenter server otherwise. In our datacenter setups, I went with the Windows based setup, because we have the Windows licensing based on Datacenter licenses from Microsoft. Also, we would like to use Update Manager (VUM) there. A thing the VCSA does not support.
In short:
1) Does your virtual infrastructure (or your customers') use the Windows or Linux based vCenter Server? What was your reason for going with one or the other?
2) In both cases, with a local database, or a remote?
3) In the Windows based vCenter case, have you installed it on physical hardware, or as a virtual machine? Why?
Everyone that shares their vision on the above questions will be given a helpfull answer. 
>>> ... DB2 for the appliance ...
Just a quick note: A DB2 datasbase was only for the first version, later DB2 was replaced vPostgres.
Answering your questions would mostly mean to repeat what you already summarized 
- It's actually a question of the environment's size. Since SQL-Express still only supports up to 5 hosts, most smaller environments benefit from the appliance. Host updates can actually be done in a single command line, so VUM is not really a requirement. Also think of the much easier maintenance of the applicane.
- Local DB where possible. Remote in larger environments or if required/requested by the customer.
- Definitely VM based. Much higher availability in case of a hardware failure. In case of hardware, you'd either need the appropriat support level for the hardware or a cold standby system. I've never setup a physical vCenter Server since the 3.x times.
André
You're right, vPostgres ofcourse . One advantage I see in VUM is the rolling upgrade variant in which VUM walks through a cluster and places each host in maintenance mode, applies the updates, reboots if necessary and then takes the host out of the maintenance mode.
Thanks for your insights. Have you ever deployed something like vCenter heartbeat to tackle (application) HA of the vCenter server?
