Shutdown one node in RAC
DISCLAIMER : Not an Oracle DBA

Use srvctl, the grid control program that allows you to manipulate parts of the RAC Cluster

Usage: srvctl &lt;command&gt; &lt;object&gt; [&lt;options&gt;]
    commands: enable|disable|start|stop|relocate|status|add|remove|modify|getenv|setenv|unsetenv|config
    objects: database|instance|service|nodeapps|vip|asm|diskgroup|listener|srvpool|server|scan|scan_listener|oc4j|home|filesystem|gns
For detailed help on each command and object and its options use:
  srvctl &lt;command&gt; -h or
  srvctl &lt;command&gt; &lt;object&gt; -h


Examples

srvctl stop database -d mydb 
srvctl stop instance -i mydb1


Please get an expert to perform these, especially since you want to do something with ASM. If I recall, ASM is a proprietary Oracle file system. Using srvctl would be better than trying to handle it yourself.

Here is more help on srvctl

$ srvctl stop database -h

Stops the database.

Usage: srvctl stop database -d &lt;db_unique_name&gt; [-o &lt;stop_options&gt;] [-f]
    -d &lt;db_unique_name&gt;      Unique name for the database
    -o &lt;stop_options&gt;        Options to shutdown command (e.g. normal, transactional, immediate, or abort)
    -f                       Force stop
    -h                       Print usage
$ srvctl stop instance -h

Stops the database instance.

Usage: srvctl stop instance -d &lt;db_unique_name&gt; {-n &lt;node_name&gt; | -i &lt;inst_name_list&gt;}  [-o &lt;stop_options&gt;] [-f]
    -d &lt;db_unique_name&gt;      Unique name for the database
    -n &lt;node_name&gt;           Node name
    -i "&lt;inst,...&gt;"          Comma separated instance names
    -o &lt;stop_options&gt;        Options to shutdown command (e.g. normal, transactional, immediate, or abort)
    -f                       Force stop
    -h                       Print usage
$ srvctl stop asm -h

Stops ASM instance.

Usage: srvctl stop asm [-n &lt;node_name&gt;] [-o &lt;stop_options&gt;] [-f]
    -n &lt;node_name&gt;           Node name
    -o &lt;stop_options&gt;        Options to shutdown command (e.g. normal, transactional, immediate, or abort)
    -f                       Force stop
    -h                       Print usage
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