To use Oracle ASM with Oracle Database releases earlier than Oracle Database 12c, you must use Local ASM or set the cardinality for Oracle Flex ASM to ALL, instead of the default of 3.
After you install Oracle Grid Infrastructure 12c, if you want to use Oracle ASM to provide storage service for Oracle Database releases that are earlier than Oracle Database 12c, then you must use the following command to modify the Oracle ASM resource (
$ srvctl modify asm -count ALL
This setting changes the cardinality of the Oracle ASM resource so that Oracle Flex ASM instances run on all cluster nodes. You must change the setting even if you have a cluster with three or less than three nodes to ensure database releases earlier than 11g Release 2 can find the
ora.node.sid.inst resource alias.