ALERT: Disable pstack Called From Diagsnap After Applying PSU/RU released between October 2017 and July 2018 to Grid Infrastructure (GI) Home on 12.1.0.2 and 12.2. (Doc ID 2422509.1)
在12c中，diagsnap调用的OS命令(其中有ssh)可能会消耗大量的CPU(Bug 27182006)，但这个问题在19c中已经得到了修复。
这个SR的问题是，可能是一次性问题。
12c以及以上版本的diagsnap是什么? [2469643.1]
如果问题复现的话，请使用下面的workaround回避此问题
oclumon manage -disable diagsnap --禁用diagsnap
oclumon manage -enable diagsnap --启用diagsnap
重启ora.crf资源
crsctl stop res ora.crf -init
crsctl start res ora.crf -init
The diagsnap logs are located in the $ORACLE_BASE/diagsnap directory for 12.1 and 12.2.0.1
How To Enable Diagsnap
$ oclumon manage -enable diagsnap
How To Disable Diagsnap
$ oclumon manage -disable diagsnap
How To Check Whether the Diagsnap is Disabled or Enabled?
$GRID_HOME/crf/admin/crf$(hostname -s).ora
https://orcl.tistory.com/entry/Disable-Diagsnap-in-Oracle-12c
因此关闭MGMTDB库，需要先将chm和cha服务关闭。
【下一步建议】
关闭MGMTDB库，可按以下步骤：
1) 关闭ORA.CHA 服务（ora.cha和mgmtdb 有依赖关系）
[root]#crsctl status res ora.chad -p | grep "DEPEND"
START_DEPENDENCIES=hard(global:ora.mgmtdb) pullup(global:ora.mgmtdb) <<<ora.cha 与mgmtdb依赖
START_DEPENDENCIES_RTE_INTERNAL=
STOP_DEPENDENCIES=hard(global:intermediate:ora.mgmtdb) <<<ora.cha 与mgmtdb依赖
STOP_DEPENDENCIES_RTE_INTERNAL=
2) 关闭ora.crf 服务（所有节点）
–- stop and disable ora.crf resource.
/bin/crsctl stop res ora.crf -init
/bin/crsctl modify res ora.crf -attr ENABLED=0 –init
crsctl stat res ora.crf -init
crsctl status res ora.crf –init -f
3) 查看并关闭ora.cha 服务
[root]# srvctl status cha
Oracle Cluster Health Analysis Service is enabled
Oracle Cluster Health Analysis Service is running on nodes: rac1
[root]# srvctl stop cha
[root]#srvctl status cha
Oracle Cluster Health Analysis Service is enabled
Oracle Cluster Health Analysis Service is not running.
4) 关闭mgmtdb 库并disable
[root]# srvctl stop mgmtdb
[root]# srvctl disable mgmtdb
[root]# srvctl status mgmtdb
Database is disabled
Database is not running.
5) 关闭mgmtlsnr 服务并disable
[root]# srvctl disable listener -l mgmtlsnr
[root]# srvctl status listener -l mgmtlsnr
Listener MGMTLSNR is disabled
Listener MGMTLSNR is not running
