— Create ACFS filesystem on 12c Linux Exadata —
1. Create a volume in ASM

ASMCMD [+] > volcreate -G datac1 -s 500G ACFS_VOL

If you get like below error

ORA-15032: not all alterations performed
ORA-15479: ASM diskgroup does not support volumes
ORA-15221: ASM operation requires compatible.asm of 12.1.0.2.0 or higher (DBD ERROR: OCIStmtExecute

Check the Current Compatibility for the Diskgroup

select group_number, name,compatibility, database_compatibility from v$asm_diskgroup
GROUP_NUMBER NAME COMPATIBILITY DATABASE_COMPATIBILITY
———— —————————— ———————————————————— ————————————————————
1 DATAC1 12.1.0.1.0 11.2.0.2.0
2 DBFS_DG 12.1.0.0.0 11.2.0.2.0
3 RECOC1 12.1.0.1.0 11.2.0.2.0
SQL> alter diskgroup DATAC1 set attribute ‘compatible.asm’=’12.1.0.2.0’;

Diskgroup altered.

SQL> alter diskgroup RECOC1 set attribute ‘compatible.asm’=’12.1.0.2.0’;

Diskgroup altered.

SQL> alter diskgroup DBFS_DG set attribute ‘compatible.asm’=’12.1.0.2.0′;

Diskgroup altered.

SQL> select group_number, name,compatibility, database_compatibility from v$asm_diskgroup;

GROUP_NUMBER NAME COMPATIBILITY DATABASE_COMPATIBILITY
———— —————————— ———————————————————— ————————————————————
1 DATAC1 12.1.0.2.0 11.2.0.2.0
2 DBFS_DG 12.1.0.2.0 11.2.0.2.0
3 RECOC1 12.1.0.2.0 11.2.0.2.0

Run again the volcreate command
ASMCMD [+] > volcreate…

The Issue

We have been running an Advanced Queuing solution for a while now, and with a frustrating regularity we were seeing messages building up in our queue table and the dequeue process seeming to think that there was no work for it to do. These were messages that had a time delay set before being ready for dequeuing. Messages queued without a delay were processed at all times.

This was a RAC system running 10.2.0.4

Perhaps the most frustrating thing about this problem was that Oracle Support effectively refused to look into the problem because we had the parameter aq_tm_processes set. Aparently the recomendation in 10g is to have this parameter unset. Of course if this parameter is currently set you can’t actually unset it without a bounce of the database, which is not something you can automatically perform.

The Workaround

While awaiting the chance to bounce the database…