My two main boxes are split to be storage vs compute. The NAS box has a minimal CPU and a pile of 3.5 drives for the low cost storage and they hypervisor has all the CPU and fairly small storage.
Basically the goal in my setup is all the working data is in one place and the handling in another with various snapshots and RAID mixed in to avoid the risk of "oh shit did I just...?" situations.
So anything that could be called bulk data gets offloaded to the NAS directly via mounts and any cache/working data is held locally. If your lab space grows to a notable level over time eventually you need to consider disk I/O as part of the design and having the bulk data on another box let's you effectively trade some network load in for disk load.