private int getMinToStart() {
    if (master.isInMaintenanceMode()) {
      // If in maintenance mode, then in process region server hosting meta will be the only server
      // available
      return 1;
    }

    int minimumRequired = 1;
    int minToStart = this.master.getConfiguration().getInt(WAIT_ON_REGIONSERVERS_MINTOSTART, -1);
    // Ensure we are never less than minimumRequired else stuff won't work.
    return Math.max(minToStart, minimumRequired);
  }
Calculate min necessary to start. This is not an absolute. It is just a friction that will
cause us hang around a bit longer waiting on RegionServers to check-in.
hbase-server/src/main/java/org/apache/hadoop/hbase/master/ServerManager.java