What on earth is running on that, Panantirs spying database ?

Do you mean the use case of a 300-node Redis Cluster?

It’s very common. Since Redis typically runs with 2 vCores per node, a 300-node cluster can only store about 2.4 TB of data.

It’s common in human-centric feature stores and profile stores. But it’s even more common in agent profile stores, since agent profiles are a much larger category.