This procedure describes how to migrate to DMP from IBM Multipath IO (MPIO) or an MPIO path control module (PCM). The procedure includes removing the devices from MPIO control and enabling DMP on the devices.
If an MPIO PCM is installed, you need to remove the PCM before you install the ODM packages from the vendor.
Plan for system downtime for the following procedure.
The migration steps involve system downtime on a host due to the following:
Need to stop applications
Need to stop the VCS services if using VCS
The procedure involves one or more host reboots
To take the devices out of MPIO control and enable DMP
If the MPIO suppression ODM fileset is not available, use the vxmpio utility to remove the device from MPIO.
# varyoffvg vgroupname
# vxdisk rm dmpnodename
If a PCM controls the rootvg devices, then you must obtain the script from the PCM vendor to uninstall the PCM. For example, if the Subsystem Device Driver Path Control Module (SDDPCM) controls the devices, then contact IBM to obtain the script to remove SDDPCM.
Some array vendors do not distribute ODM Pre-defines for their arrays for AIX. In this case, you can use the devices as hdisk devices, as long as MPIO does not claim these LUNs.
# vxdmpadm settune dmp_native_support=on
The above command also enables DMP support for LVM root.