> But the nexus is also capable of performing transformations on the I/O passing through it. For example, for reasons of availability and durability, we might wish to maintain more than one copy of the data contained by a PV. The nexus supports this by dispatching multiple copies of any writes which are received for the volume, to replicas hosted on other Mayastor Storage Nodes within the cluster (the actual replica count is defined by the Volume’s Storage Class). Only when all replicas have acknowledged their writes will the nexus signal completion of the transaction back to the consumer. That is to say, policy-based workload protection in Mayastor is based on synchronous replication.

Presumably life can go on so long as a replica survives.

> MOAC’s response to the available replica count of a Volume falling below the desired count defined within its Storage Class is to instruct a Mayastor Storage Node to create a new, “empty” replica, and to share it with the degraded nexus. The introduction of a new replica to the nexus will cause it to start a rebuild process, bringing it into synchronization with the other replicas. This process can successfully complete without having to suspend workload I/O to the affected PV.