You just rebooted a server that you know that runs Oracle RAC and the other node rebooted. This happened because CRS was active and you first need to disable to reboot the other node. You’ll see this message on /var/adm/messages
Jun 5 14:15:19 solaris_rac2 root: Oracle clsomon failed with fatal status 12.
Jun 5 14:15:20 solaris_rac2 root: Oracle CRS failure. Rebooting for cluster integrity.
rebooting…
Run this command to stop CRS. Your path may vary according to where you installed the binary.
root@solaris_rac1:~ # /u01/app/oracle/product/11.1.0/bin/crsctl stop crs
Stopping resources.
This could take several minutes.
Successfully stopped Oracle Clusterware resources
Stopping Cluster Synchronization Services.
Shutting down the Cluster Synchronization Services daemon.
Shutdown request successfully issued.
Check the status with crsctl check crs. It should display the message below
root@solaris_rac1:~ # /u01/app/oracle/product/11.1.0/bin/crsctl check crs
Failure 1 contacting Cluster Synchronization Services daemon
Cannot communicate with Cluster Ready Services
Cannot communicate with Event Manager
After you reestablish the machine, CRS should start automatically
root@solaris_rac1:~ # /u01/app/oracle/product/11.1.0/bin/crsctl check crs
Cluster Synchronization Services appears healthy
Cluster Ready Services appears healthy
Event Manager appears healthy
setaOffice 