Last updated on OCTOBER 31, 2016
Applies to:Oracle Database - Enterprise Edition - Version 188.8.131.52 and later
Information in this document applies to any platform.
***Checked for relevance on 09-Jul-2014 ***
2. ASM spfile has been created on ASM diskgroup.
3. Add some ASM diskgroup to spfile dynamically.
SQL> alter system set asm_diskgroups='DATA','FRA' scope=both sid='+ASM';
4. crsctl stop crs
5. crsctl start crs << FRA ASM diskgroup is not mounted.
SQL> show parameter asm_diskgroups
NAME TYPE VALUE
asm_diskgroups string DATA
6. Create pfile from spfile show there is FRA ASM diskgroup added.
SQL> create pfile='/tmp/init+ASM.ora' from spfile ;
SQL> !cat /tmp/init+ASM.ora
+ASM.__oracle_base='/orasw/adr'#ORACLE_BASE set from in memory value
7. From alert_ASM.log, you see FRA ASM diskgroup is dismounted individually by asm agent before ALTER DISKGROUP ALL DISMOUNT /* asm agent */
NOTE: diskgroup resource ora.FRA.dg is offline
SUCCESS: ALTER DISKGROUP FRA DISMOUNT /* asm agent */
ALTER DISKGROUP ALL DISMOUNT /* asm agent */
Please find the following 11gR2 doc regarding automatic update asm_diskgroup parameter.
Oracle Database Reference 11g Release 2 (11.2)
ASM_DISKGROUPS specifies a list of names of disk groups to be mounted by an Automatic Storage Management instance at instance startup. Oracle ignores the value that you set for ASM_DISKGROUPS when you specify the NOMOUNT option at startup or when a ALTER DISKGROUP ALL MOUNT statement is issued.
Automatic Storage Management (ASM) automatically adds a disk group to this parameter when the disk group is successfully created or mounted, and automatically removes a disk group from this parameter when the disk group is dropped or dismounted.
Issuing the ALTER DISKGROUP...ALL MOUNT or ALTER DISKGROUP...ALL DISMOUNT command does not affect the value of this parameter.
This issue rises with a combination of automatic update on ASM spfile and manual dismount ASM diskgroup by asm agent on shutting down CRS.
According to the doc, ALTER DISKGROUP...ALL DISMOUNT command does not affect the value of this parameter.
But for some reasons ( maybe no dependency between asm and asm diskgroup ), on CRS shutdown, each diskgroup is dismounted individually before ASM is down, which is considered that the ASM diskgroup is dismounted manually and spfile is updated accordingly. This affects the next startup.
Unless there is any dependency, ASM diskgroups won't be mounted automatically on startup as they are considered being dismounted manually by asm agent in previous shutdown.
It appears that there is no dependency between ASM diskgroup and ASM instance as manual ASM shutdown using sqlplus doesn't cause this issue.
With this finding, once you create a dependency on ASM diskgroup with a database, it will mount correponding ASM diskgroups no matter what happens on CRS shutdown.
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