ASMLIB createdisk problem on emcpower devices — solved

If you are using ASMLIB library to label ASM disks on Red Hat Enterprise Linux 5.X or SuSE Linux Enterprise Server 10/11 systems with EMC PowerPath as your multipathing software you may encounter the following error while running the oracleasm createdisk command:

#/etc/init.d/oracleasm createdisk DATA01 /dev/emcpowera1
Marking disk "/dev/emcpowera1" as an ASM disk:
asmtool: Device "/dev/emcpowera1" is not a partition
[FAILED]

This is due to the EMC PowerPath bug #285242 which makes  it to not properly support the sd_getgeo() i/o calls that oracleasm makes, as mentioned in the Oracle Metalink document 469163.1 and EMC Powerlink document emc203137

The workaround to overcome this problem is to use the asmtool command with “-a force=yes” option.

#/usr/sbin/asmtool -C -l /dev/oracleasm -n DATA01 -s /dev/emcpowera1 -a force=yes
asmtool: Device "/dev/emcpowera1" is not a partition
asmtool: Continuing anyway

asmtool will also complain that the device is not a partition but it will put the asmlib header on the device and create the related device file under /dev/oracleasm/disks/ directory. However it will leave the device file with root:root as the owner and group. Restarting the asmlib service will solve this problem.

service oracleasm restart

The actual solution has arrived with PowerPath for LINUX 5.3.1 for RHEL and PowerPath for LINUX 5.3.2 for SLES 11. After updating to this release oracleasm createdisk command works flawlesly as expected.

#oracleasm createdisk DATA02 /dev/emcpowerb1
Writing disk header: done
Instantiating disk: done

There are some other very important bugs solved in Powerpath releases 5.3 and 5.3 SP1 like “Dynamic addition of large number of LUNs may result in a host hang” and “PowerPath: emcpmgr processes are causing high load during startup” so there is good reason to update to the latest Powerpath release.

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One response to this post.

  1. Thank you for a great issue with using asmtool command with “-a force=yes” ;)

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