I think Minerva is clearly a reference to Athena.

Could be a misdirection because all of the rest fits Quartz to a tee.

The Quartz database is called Sandra (referred to as Barbara here).

The Quartz directed acyclic graph is called Dag (referred to as Dagger here)

The Quartz job runner is called Bob (referred to as Walpole here which is a reference to Robert Warpole whose shortname is..Bob)

These and the horrible proprietary IDE make it obvious which particular system he's describing.

How are the Barbara databases synchronized - as multiple nodes are mentioned ? The description makes it sound like it's just a large set of pickles in something like a Berkley DB?

Each server in a ring has a complete copy of the data for that ring. Each ring consists of a network of servers which may have nodes in different geographies. They're called rings, but are actually acyclic networks (IIRC).

Replication occurs automatically so you need to manage consistency in your app architecture. For example if you have instances of an app running in different geographies, the specific data for those instances should be in different folders.

I think Athena has equivalents to all of these but I don't know what they're called. I only know Qz.

The Athena database is Hydra; The Athena graph is Pixie; The Athena job runner is also Bob

I find it amusing that Bob made it in most of the banks, but few of the other names stuck.