Once I had a handle on the requirements it was time to begin investigating suitable kit to buy. Two resources I found invaluable for this purpose were the website uk.pcpartpicker.com and the experience and advice of my colleague Jonathan who had recently built his own home lab.
My initial thoughts were to build three ESXi servers and configure them as a vSAN cluster for storage. This would give me the ability to source motherboards with just 4 DIMM slots and buy 32GB memory kits (components which are very common and therefore priced more competetively) for a total of 96GB of memory in the cluster. However the ability to power down these machines when not in use was one of my primary requirements. Three is the smallest number of nodes you can have in a vSAN cluster, which allows the tolerance of one host failure. Constantly putting the cluster into a compromised state by shutting down hosts didn't seem like a very good idea to me.
I don't have a lot of experience of vSAN at the moment, so relying on it as the storage to underpin my entire lab seemed like it could be a bit of a disaster. In the end, I decided that the best approach would still be to build three systems, but to make one of them a dedicated storage server. This would give me the flexibility to power down all of the hosts easily, provided it was done in the correct order.
The final kit list I decided upon is available as a Google Docs spreadsheet. The prices are accurate at the time of writing, but delivery costs are not shown. In total delivery charges probably bump the total cost up by about £50.
In Part 4 I'll be looking at a high-level design for my new lab environment.