asm 11g compatibility settings and conversion to H.A.R.D format
Posted by John Hallas on December 12, 2008
When using ASM with 11g and taking the default settings from a DBCA build the following line can be seen in the asm alert_log
Spfile /app/oracle/product/11.1.0/asm/dbs/spfile+ASM.ora is in old pre-11 format and compatible >= 11.0.0; converting to new H.A.R.D. compliant format
Firstly H.A.R.D. refers to Oracle’s Hardware Assisted Resilient Data (H.A.R.D) Initiative which Metalink note 227671.1 summarises as
To use HARD validation, all datafiles and log files are placed on HARD-compliant storage.
The user must also enable the HARD validation feature on the storage, using the vendor-provided interface. When Oracle writes data to the storage, the storage system validates the data. If it appears to be corrupted, then the write is rejected with an error.
The sql commands here are taken from an excellent note on the Pythian site by Alex Gorbachev http://www.pythian.com/blogs/1078/oracle-11g-asm-diskgroup-compatibility.
In short the compatibility settings allow ASM to manage databases from both 10g and 11g. As this was an 11g environment only I felt comfortable in amending the parameters.
The compatible.asm parameter defines the minimum version of the asm software that is using the disk groups. As the format of the metadata on the disk changes from asm 10 to asm 11 then this setting defines that format. This will be non-reversible.
rdbms.compatible defines the minimum version of the rdbms compatible parameter for any databse that uses the asm disk groups.
Restart the database and lo and behold, no spfile compatibility error