问题现象：
Oracle集群好像不漂移IP了，全部会话连接数量只集中在某个节点上，这个节点断掉也不会自动连接到另外一个节点上；
问题排查：
在节点RAC1上执行集群状态检查命令（注意看红色字体部分）：
grid@rac01:[/home/grid]crsctl stat res -t
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NAME TARGET STATE SERVER STATE_DETAILS
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Local Resources
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ora.ARDATA.dg
ONLINE ONLINE rac01
ONLINE ONLINE rac02
ora.CLDATA.dg
ONLINE ONLINE rac01
ONLINE ONLINE rac02
ora.LISTENER.lsnr
ONLINE ONLINE rac01
ONLINE ONLINE rac02
ora.USDATA.dg
ONLINE ONLINE rac01
ONLINE ONLINE rac02
ora.USDATA01.dg
ONLINE OFFLINE rac01
ONLINE ONLINE rac02
ora.asm
ONLINE ONLINE rac01 Started
ONLINE ONLINE rac02 Started
ora.gsd
OFFLINE OFFLINE rac01
OFFLINE OFFLINE rac02
ora.net1.network
ONLINE ONLINE rac01
ONLINE ONLINE rac02
ora.ons
ONLINE ONLINE rac01
ONLINE ONLINE rac02
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Cluster Resources
--------------------------------------------------------------------------------
ora.LISTENER_SCAN1.lsnr
1 ONLINE ONLINE rac02
ora.cvu
1 ONLINE ONLINE rac02
ora.oc4j
1 ONLINE ONLINE rac02
ora.rac01.vip
1 ONLINE ONLINE rac01
ora.rac02.vip
1 ONLINE ONLINE rac02
ora.racdb.db
1 ONLINE OFFLINE Instance Shutdown
2 ONLINE ONLINE rac02 Open
ora.scan1.vip
1 ONLINE ONLINE rac02
由此发现可能USDATA01卷组不能正常工作，尝试启动USDATA01卷组，发现继续报错。