srvctl

Use the following syntax to add configuration information about an existing ASM instance:
srvctl add asm -n node_name -i asm_instance_name -o oracle_home
Use the following syntax to remove an ASM instance:
srvctl remove asm -n node_name [-i asm_instance_name]
Use the following syntax to enable an ASM instance:
srvctl enable asm -n node_name [-i ] asm_instance_name
Use the following syntax to disable an ASM instance:
srvctl disable asm -n node_name [-i asm_instance_name]
The above statement is generally required when u want to disable the asm so that asm does not start automatically on reboot.

You can also use SRVCTL to start, stop, and obtain the status of an ASM instance as in the following examples.
Use the following syntax to start an ASM instance:

srvctl start asm -n node_name [-i asm_instance_name] [-o start_options] [-c | -q]
Use the following syntax to stop an ASM instance:
srvctl stop asm -n node_name [-i asm_instance_name] [-o stop_options] [-c | -q]
Use the following syntax to show the configuration of an ASM instance:
srvctl config asm -n node_name
Use the following syntax to obtain the status of an ASM instance:
srvctl status asm -n node_name
Use the following syntax to stop the database on anyone of the nodes in an RAC environment:
srvctl stop listener -n node_name
srvctl stop instance -d -i -o immediate
Use the following syntax to start the database on anyone of the nodes in an RAC environment:
srvctl start listener -n node_name
srvctl start instance -d -i -o immediate
Use the following command to stop the database using single command:
srvctl stop database -d -o immediate
In order to stop the node applications like oracle vip,gsd, ons services ,use following commands
srvctl stop nodeapps -n
Similarly to start
srvctl start nodeapps -n
If u wish to trun srvm trace on which can be useful for diagnosisi during instance startup or shut dowm use following command:
SRVM_TRACE=TRUE; export SRVM_TRACE
srvctl stop asm -n -i +ASM1 -o immediate>srvctl_stop_asm.log
Similarly
srvctl stop instance -d db_name -i instance_name -o immediate > srvctl_stop_instance.log