[HDDS-9596] Determine the criteria for calling a container empty in the SCM

• Type: Sub-task
• Status: Open
• Priority: Major
• Resolution: Unresolved
• Component/s: SCM
• Target Version/s: 2.0.0
• Assignee: Unassigned
• Reporter: Siddhant Sangwan
• Created: 31/Oct/23 14:51
• Updated: 16/Dec/23 23:43

Description

This is the current apache master logic for identifying an empty container:

  private boolean isContainerEmptyAndClosed(final ContainerInfo container,
      final Set<ContainerReplica> replicas) {
    return container.getState() == HddsProtos.LifeCycleState.CLOSED &&
        !replicas.isEmpty() &&
        replicas.stream().allMatch(
            r -> r.getState() == ContainerReplicaProto.State.CLOSED &&
                r.isEmpty());
  }

What happens if: For an open container, a write is successful in 2 replicas, but not in the 3rd one. Now the pipeline is broken and closed and this container moves to quasi closed. The replicas are also quasi closed. It has two replicas on unique origins, so then the container is closed. At this stage, the quasi closed replicas go down and we’re only left with the 3rd empty replica. Won’t we be wrong in marking this container as empty now?

Issue Links

• is required by: HDDS-9595 Investigate QUASI_CLOSED containers with only one UNHEALTHY and empty replica