Migrating from SDDPCM to AIXPCM (the easy way)

For a while now, IBM have diverted their efforts in storage multipathing from SDDPCM to the default AIX PCM [1]. This brings a few advantages, but specifically for me, it means the driver is now updated as part of the AIX system maintenance, and is no longer something I need to maintain separately. All significant functionality that SDDPCM provides, can now be provided by the default AIX PCM driver. Additionally, SDDPCM is not supported on POWER 9 hardware.

For those currently using SDDPCM, removing the driver can be somewhat complicated, and even more so when the boot LUN (rootvg LUN) is being managed by SDDPCM. Buried deep in the Multipath Subsystem Device Driver User’s Guide is a command called manage_disk_drivers. The manage_disk_drivers command can be used to display a list of storage families, and the driver that manages or supports each family. This allows us to easily (with a reboot if you boot from an SDDPCM managed device) switch the driver from SDDPCM to AIXPCM (or vice versa).
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