For example, 100GB data is relatively small. Would easily fit in a single AWS i3.large. But what's going to be your analytical load? How many queries per second are you going to run? A few, or a lot? Just limited traversals or very broad-ranging queries? What sort of latencies are tolerable? Are you looking for millisecond-scale response times (<10ms) or is multi-second query responses acceptable.

If you want fast response then you're looking at directly-attached NVMe. If you really don't care about the latencies you can use EBS.

-Peter.