Design a Synchronously Replicated Hash Map

Design Overview We need an active–passive replicated hash map with one writer and one reader. The map supports put(key, value), get(key), and remove(key). The central requirement is: A write is successful only if it has been durably applied on the active node and durably replicated to the passive node. Otherwise the write fails. The active node serves both writes and reads. The passive node is a hot standby; it does not serve client traffic unless the active fails and it is…