[PDS-212988] AZ check for nonstandard topology

[jeremyk-91]

A cluster with one node in one AZ (say A) and two in another (say B) is actually at risk of an outage if the availability zone B with 2 nodes in fails. This should be recognised as a very much nonstandard topology.

[leonz]

There are many datacenters that only have 2 AZs, so this topology is sometimes unavoidable.

[sudiksha27]

We are only looking at TimeLock for this issue - are you referring to Cassandra concept of datacenters or physical concept of datacenters?

[leonz]

No, I'm referring to physical datacenters / Amazon AZs.