切换前状态检查
检查主备库运行状态：
echo 'ROLE$: 0 Noraml, 1 Primary, 2 Standby'
disql -S / as sysdba <<EOF
select name,instance_name,status$,mode$ from v\$instance;
select name,status$,role$ from v\$database;
exit
EOF
${DM_HOME}/bin/DmWatcherService${DB_NAME} status
${DM_HOME}/bin/DmService${DB_NAME} status
检查监视器在哪台服务器上：
[dmdba@DMHOST_IP_1 ~]
