APPLIES TO:

Oracle Database - Enterprise Edition - Version 12.1.0.2 and later
Information in this document applies to any platform.
Oracle 企业版，从12.1.0.2和以后的版本，适用于任何平台。

PURPOSE

To understand the new behavior, from 12.1.0.2, of which node will survive when split brain takes place.
为了更好的理解从12.1.0.2以后的版本出现脑裂，哪个节点会存活下来。

DETAILS

In 11.2 or even older version, the lowest number node will survive when split
brain takes place, however this has changed in 12.1.0.2 with the introduction of
node weight. Started from 12.1.0.2, during split brain resolution, node with
higher weight will survive:
--在11.2和之前的版本，当出现脑裂的时候，节点号小的会存活。但是从12.1.0.2以后发生了变化，引入了权重的概念，当出现脑裂的时候，权重高的节点会存活下来。

2014-11-24 14:25:41.140603 : CSSD:1117321536: clssnmrCheckNodeWeight: node(1) has weight stamp(0), pebble(0)
2014-11-24 14:25:41.140609 : CSSD:1117321536: clssnmrCheckNodeWeight: node(2) has weight stamp(311972654), pebble(3)
2014-11-24 14:25:41.140612 : CSSD:1117321536: clssnmrCheckNodeWeight: stamp(311972654), completed(1/2)
2014-11-24 14:25:41.140615 : CSSD:1117321536: clssnmrCheckSplit: Waiting for node weights, stamp(311972654)
2014-11-24 14:25:41.188880 : CSSD:1084811584: clssnmvDiskKillCheck: not evicted, file /dev/raw/raw2 flags 0x00000000, kill block unique 0, my unique 1416805718
2014-11-24 14:25:41.558921 : CSSD:1114167616: clssnmvDiskPing: Writing with status 0x3, timestamp 1416810341/1022717334
2014-11-24 14:25:41.731912 : CSSD:1086388544: clssnmvDHBValidateNCopy: node 1, node1, has a disk HB, but no network HB, DHB has rcfg 311972655, wrtcnt, 9527468, LATS 102 2717514, lastSeqNo 9527467, uniqueness 1416808381, timestamp 1416810341/1022722074
2014-11-24 14:25:41.731928 : CSSD:1086388544: clssnmvReadDskHeartbeat: manual shutdown of nodename node1, nodenum 1 epoch 1416810341 msec 1022722074
2014-11-24 14:25:41.732266 : CSSD:1117321536: clssnmrCheckNodeWeight: node(2) has weight stamp(311972654), pebble(3)
2014-11-24 14:25:41.732273 : CSSD:1117321536: clssnmrCheckNodeWeight: stamp(311972654), completed(1/1)
2014-11-24 14:25:41.732294 : CSSD:1117321536: clssnmCheckDskInfo: My cohort: 2
2014-11-24 14:25:41.732299 : CSSD:1117321536: clssnmRemove: Start
2014-11-24 14:25:41.732306 : CSSD:1117321536: (:CSSNM00007:)clssnmrRemoveNode: Evicting node 1, node1, from the cluster in incarnation 311972655, node birth incarnation 311972654, death incarnation 311972655, stateflags 0x225000 uniqueness value 1416808381 The number of the resource executing on each node and others are considered by the weight. Reference

大家只需要知道不同的版本会有很大的变化，要不断的去查看官方文档。