oracleasm createdisk : Device '/dev/emcpowera1 is not a partition

ASMLib: oracleasm createdisk command fails: Device '/dev/emcpowera1 is not a partition [Failed] [ID 469163.1]

 

Symptoms
The "oracleasm createdisk" command fails with the following error despite the device having been correctly partitioned:

Marking disk "/dev/emcpowera1" as an ASM disk: asmtool: Device "/dev/emcpowera1" is not a
partition         [FAILED]

Changes
You are using EMC PowerPath version <= 5.3.0
Cause
EMC PowerPath versions <= 5.3.0 do not properly support the I/O calls performed by oracleasm.
Solution
The issue is resolved with EMC PowerPath version 5.3 SP1 (5.3.1) - refer:

    * EMC� PowerPath Family for Linux Version 5.3 Release Notes - January 25, 2010 (Fixed Problems)
    * EMC Knowledgebase Solution emc203137

EMC PowerPath 5.3.1 is readily available from EMC's Powerlink website (login required) i.e.:

> Support > Software Downloads & Licensing > Downloads P-R > Powerpath for Linux

If it is not currently possible to upgrade to the latest version of PowerPath containing the fix, the following workaround is possible:

1. Perform. the "oracleasm createdisk" operation using the "asmtool" command directly e.g.:

# /usr/sbin/asmtool -C -l /dev/oracleasm -n VOL1 -s /dev/emcpowera1 -a force=yes

The asmtool will (expectedly) report the following:

asmtool: Device "/dev/emcpowera1" is not a partition
asmtool: Continuing anyway
...

2. The user/group ownership of the resultant devices under directory /dev/oracleasm/disks/ will be "root:root" therefore may not be immediately accessible to other user processes.

However, ownership can be manually modified using the chown(1) command. Specify the user:group as defined in oracleasm configuration file /etc/sysconfig/oracleasm (ORACLEASM_UID, ORACLEASM_GID) or by restarting  the oracleasm service e.g.:

# /sbin/service oracleasm restart

If restarting the oracleasm service is not effective, system reboot is required.

3. Once the asmdisk has been successfully created, further use of the device can now be performed normally using the "/etc/init.d/oracleasm" command against the PowerPath pseudo device e.g. /dev/emcpowera1.

References
BUG:6605620 - ORACLEASM CREATEDISK FAILS: DEVICE "/DEV/EMCPOWERB2" IS NOT A PARTITION [FAILED]