4.2.2 How to Stop Sun Cluster on All Nodes
You might want to shut down all nodes in a Sun Cluster configuration if a hazardous environmental condition exists, such as a cooling failure or a severe lightning storm.  
- 
Stop the membership monitor on all nodes simultaneously by using the scadmin(1M) command. You can do this in one step using the Cluster Console.  
| phys-hahost1# scadmin stopnode
... |  
 
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Halt all nodes using halt(1M).