On the new rebuild database servers - after installing oracle crs/asm 22.214.171.124 and oracle rdbms binary for 10.2.0.1, 10.2.0.2 and 126.96.36.199 + apply 11g rdbms patches.
We got this error when trying to open the database under 10g environment variable
ALTER DATABASE MOUNT
Sat Jun 11 12:09:03 2011
ORA-00202: control file: '+SID_DBF_DG/SID/controlfile/current.355.714385251'
ORA-17503: ksfdopn:2 Failed to open file +SID_DBF_DG/SID/controlfile/current.355.714385251
ORA-15001: diskgroup "SID_DBF_DG" does not exist or is not mounted
ORA-15077: could not locate ASM instance serving a required diskgroup
ORA-29701: unable to connect to Cluster Manager
CauseThe reason here is that the cluster configuration in 11gR2 is dynamic. This dynamic configuration is incompatible with older database releases, which require a fixed configuration.
SolutionTo run older databases on 11gR2 ASM and Clusterware you need to create a persistent configuration for the nodes on which these databases are meant to run. This is called pinning a node.
Metalink Note :949073.1