What is an `abnormal cluster?
AAccording to the iAS documentation, an abnormal cluster is one with more than one primary, or no primary. A multiple-primary state can arise when a primary becomes disconnected from the network (e.g., cable failure), a secondary is promoted to be primary, and then the old primary is reconnected. A no-primary state exists whenever a primary fails, and no secondary is available to be promoted. This will be the case momentarily whenever a primary fails, but the admin process will promote a secondary to resolve it. It is not documented how long a cluster must be without a primary before it is considered to be abnormal.
