One of the challenges with running ESXi or even ZFS on the HP MicroServer N36L, N40L or N54L is the 8GB RAM limitation detailed in the hardware specs. Fortunately, running 16GB ECC RAM is a fairly easy and painless process if you get the right RAM modules.
In my scenario, I wanted 16GB ECC in my N54L so that I could maximise what I could allocate to my VMs under ESXi. After trawling through various forums I came across a certain 2x8GB Kingston kit that has been working 100% of the time. Some kits work sometimes and not others so it’s important to get the right one. The Kingston 16GB ECC kit I grabbed was KVR1333D3E9SK2/16G.
Post install, the N54L booted up every time showing a total of 16GB as expected. Loading ESXi also confirmed that the full amount was recognised and available for use.