With redundancy being the key feature of an ha cluster, the components that are essential in this example are node management, a distributed file system, volume management, and monitoring.
由于冗余是ha集群的关键特性，因而在这个例子中基本的组成部分包括节点管理、分布式文件系统、卷管理和监控。
Fixed node Hierarchy: This feature supports the ability to determine cluster leadership, auto merge groups, and node discovery where multicast might not work.
固定的节点层级：这一特性支持确定集群领导、自动合并组以及在多点传送不工作的地方发现节点。
A JMX based node monitoring feature was also added.
增加了一个基于JMX的节点监测特性。
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