I only skimmed this, and I'll go back and read it later, but I think the issue he's mentioning is price?
It's true that on Dynamo, large item sizes get very expensive, very quick. That stems from your data being stored on SSD--and with a replication factor of 3 (iirc).
Cloud or no cloud, Amazon or not, SSD storage is still a lil pricey.
Lots and lots of small items also costs though, because there's a 100byte per k/v pair overhead. So if you're storing 2GB of 100 byte k/v pairs, you have to pay for 4GB of storage.
If you store lots and lots, you probably also have either high read, high write, or high read/write rates, in which case you'll need to pay more per hour as well.
It's true that on Dynamo, large item sizes get very expensive, very quick. That stems from your data being stored on SSD--and with a replication factor of 3 (iirc).
Cloud or no cloud, Amazon or not, SSD storage is still a lil pricey.