// If some storage classes are not satisfied, don't trash any
// excess replicas. (E.g., if someone desires repl=1 on
// class=durable, and we have two copies on class=volatile, we
// If some storage classes are not satisfied, don't trash any
// excess replicas. (E.g., if someone desires repl=1 on
// class=durable, and we have two copies on class=volatile, we