ASM Is Not Detecting Raw Devices Or Regular Raw Devices On AIX (Doc ID 1174604.1)

Last updated on OCTOBER 03, 2016

Applies to:

Oracle Database - Enterprise Edition - Version 10.2.0.1 to 12.1.0.2 [Release 10.2 to 12.1]
Information in this document applies to any platform.
***Checked for relevance on 05-Feb-2015***

Symptoms

ASM is unable to detect EMC PowerPath raw devices or regular raw devices on AIX (on RAC or Standalone configurations).

1) /dev/rhdiskpower## disks are correctly owned by oracle & dba group:

crw-rw---- 1 oracle dba 36, 10 Aug 05 17:16 /dev/rhdiskpower10


2) Based on the next document:

ASM and Multipathing Best Practices Info Matrix

You are using the correct EMC powerpath disk:

On AIX: ASM can use concurrent logical raw logical volumes or raw partitions. Must use the pseudo device: /dev/rhdiskpower##


3) You tested the /dev/rhdiskpower10 disk on both ASM instances (+ASM1 & +ASM2) with the same results, the /dev/rhdiskpower10 disk is detected at OS level and belongs to Oracle OS user & DBA group but it is not being discovered by ASM:

SQL> show parameter asm_disk

NAME TYPE VALUE
------------------------------------ -----------
------------------------------
asm_diskgroups string
asm_diskstring string /dev/rhdisk*

SQL> select * from v$asm_disk;

no rows selected


SQL> ! ls -l /dev/rhdiskpower10
crw-rw---- 1 oracle dba 36, 10 Aug 05 17:16 /dev/rhdiskpower10


SQL> alter system set asm_diskstring='/dev/rhdiskpower10';

System altered.

SQL> show parameter asm_disk

NAME TYPE VALUE
------------------------------------ -----------
------------------------------
asm_diskgroups string
asm_diskstring string /dev/rhdiskpower10

SQL> select * from v$asm_disk;

no rows selected

SQL> create diskgroup test external redundancy disk '/dev/rhdiskpower10';
create diskgroup test external redundancy disk '/dev/rhdiskpower10'
*
ERROR at line 1:
ORA-15018: diskgroup cannot be created
ORA-15031: disk specification '/dev/rhdiskpower10' matches no disks

SQL> show parameter asm

NAME TYPE VALUE
------------------------------------ -----------
------------------------------
asm_diskgroups string
asm_diskstring string /dev/rhdiskpower10
asm_power_limit integer 1


4) OS logs do not report any problem on both nodes.

5) EMC power path configuration seems in good shape.

Cause

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