Seeking advice: planning a small vSphere cluster

[tlyczko]

I am seeking general advice/information about what should be considered in creating a very small vSphere cluster.

This is a ‘greenfield’ installation, initially thought and planned to be only one vSphere host, with more hosts added if and when necessary.

It’s intended to host vCenter appliance, vCenter server (VUM function), one (or two) Windows domain controllers, 3-4 application servers (SQL Server-based applications), RDSH servers and hosts to serve the client applications.

The initial idea has been 96-128 GB of RAM (TBD), local DAS storage and two 6- or 8-core processors (TBD).

I do not know how much future user or storage growth to plan for. The initial user pool is 35-50 users.

I realize that having only one vSphere host, though the initial idea is that this keeps costs down, poses risks vis-à-vis HA, downtime for host updates, and SPOF (e.g. any hardware issue makes it impossible for people to do their work).

This is a small SMB environment, periodic downtime will just have to be accepted if they are only willing to spend for one host server.

Other people involved seem to be thinking and planning on a much shorter timeframe than I am. I am trying to think 2-3 years ahead as well as for this year.

However, thinking ahead to the future, what are good arguments, justifications for having two host servers, with internal storage?? Or for using some sort of NAS (any suggestions for an appropriate NAS??) with SAS drives for shared storage?? I don’t think SAN complexity is worth it until one has 3 or more host servers, and I don’t envision 3 hosts for several more years, there’s not yet enough apps running (I do not have a crystal ball, smile!!).

As to maker and brand, it most likely would be an HP Gen8 server – though I don’t know how soon it will be superseded by newer servers. I don’t know anything about Dell servers therefore I know no reasons to prefer Dell.

Finally it will likely be a vSphere Essentials Plus installation.

Any/all comments will be read eagerly.

Thank you, Tom

[rh5592]

In my opinion, for such a small environment, if your customer is willing to accept the risk of putting their eggs in one basket for the sake of cost, then there is not much argument we can make. But moving forward, it is always good to point them to the benefits  of having a highly available environment. If you are using Essentials plus, with a single host you are basically throwing away the functionalities bundled with it (HA, vMotion). On the other hand, a two host cluster without shared storage, you can get vMotion without shared storage functionality but HA will not be there.

On another perspective, you may want to look at checking if VSAN is a good use case for this environment. Though it requires a minimum of 3 hosts, the ease of use, HA, vMotion, policy based model, no need for external storage, scale out approach is a very tempting approach.