A technique provides data high availability to a set of host computers. The technique involves, while a production array provides the set of host computers with access to a production logical unit of storage (LUN), replicating data from the production LUN to a replicated LUN on a replication array. The technique further involves, after replicating at least some of the data from the production LUN to the replicated LUN, electronically detecting a production array deficiency. The technique further involves, in response to electronically detecting the production array deficiency, automatically performing, by electronic circuitry, a failover operation which (i) terminates providing the set of host computers with access to the production LUN and (ii) provides the set of host computers with access to the replicated LUN on the replication array.