I find it incredibly hard to believe that ultima online was the first application of database sharding, but it may very well be the source of the name. "key-based partitioning" doesn't have the same ring to it, but has existed since the early 90's and possibly late 80's.
I can't seem to find it right now, but I read an article, shared in the "awesome-scalability" GitHub repo, which referenced a 1978 paper, written by a couple of IBM researchers, about sharding and a lot of seemingly modern database things.
Agreed. I have worked at a Fortune 100 firm where its business ran (still runs) off of an ERP sharded into 100 instances, each representing one key facility since the mid-90s. It took extra work in the early days to centralize analytics and manage deployments and data, but it has been very resilient (low blast radius in today's terminology) and natural for low risk deployments, rolling out of upgrades to one site, then the rest in batches.
