EMC AIX ODM package

Dilemma of the day: to install or not to install the EMC AIX ODM package on AIX 5.3 machines connected to an EMC DMX SAN??

This is from the AIX 5.3 release notes:

A device configured as MPIO other FC disk has the following properties:
[...]
Is supported in a production environment. Device-specific vendor ODM pre-definitions are not required to be installed before using in a production environment.

So, I install my machines with the default AIX configuration and they run happily for weeks with EMC disks configured as "MPIO Other FC SCSI Disk Drive", with no problems whatsoever.

Today I find this in the "EMC Host Connectivity Guide for IBM AIX":

A Symmetrix device configured as an MPIO other FC device is not
supported. The only supported configuration is with the EMC
Symmetrix FCP MPIO ODM predefined attributes which has been
certified to operate with the AIX default PCMs. These predefines get
installed with the EMC.Symmetrix.fcp.MPIO.rte fileset.

My machines haven't gone into production yet, but some will very soon. So now I have to varyoff the VGs, delete the disks, install the goddamn EMC filesets (which does a bosboot), and reboot each machine. Luckily I only have ten machines so far.

According to the same EMC doc, two filesets are necessary, from the following two combinations:

EMC.Symmetrix.aix.rte
EMC.Symmetrix.fcp.rte

or

EMC.Symmetrix.aix.rte
EMC.Symmetrix.fcp.MPIO.rte

The former configures the disks without MPIO (lspath shows nothing for those disks), while the latter configures them as MPIO devices with a path to each HBA they are connected to.

But can EMC.Symmetrix.fcp.rte and EMC.Symmetrix.fcp.MPIO.rte coexist? No, they can't. This is what happens if you try to install the two at the same time:

*************************************************************************
* EMC Symmetrix FCP MPIO Software Support for Symmetrix devices has *
* been found installed or Symmetrix FCP Software Support is being *
* installed simultaneously. It is necessary to remove all previous *
* versions of the EMC.Symmetrix.fcp.MPIO.rte software before Symmetrix *
* FCP Software Support can be installed. *
* Select the correct software fileset to install or run the following *
* command to remove the EMC.Symmetrix.fcp.MPO.rte software. *
* *
* Please run 'installp -u EMC.Symmetrix.fcp.MPIO.rte' to remove the *
* installed fileset. *
* *
*************************************************************************
instal: Failed while executing the EMC.Symmetrix.fcp.rte.pre_i script.

*************************************************************************
* EMC Symmetrix FCP Software Support for Symmetrix devices has been *
* found installed or Symmetrix FCP MPIO Software Support is being *
* installed simultaneously. It is necessary to remove all previous *
* versions of the EMC.Symmetrix.fcp.rte software before Symmetrix FCP *
* MPIO Software Support can be installed. *
* Select the correct software fileset to install or run the following *
* command to remove the EMC.Symmetrix.fcp.rte software *
* *
* Please run 'installp -u EMC.Symmetrix.fcp.rte' to remove the *
* installed fileset. *
* *
*************************************************************************
instal: Failed while executing the EMC.Symmetrix.fcp.MPIO.rte.pre_i script.

So, it's either one or the other. Why the hassle, you may ask? Thing is, right now we do not have multiple HBA attachments for the same disks. In this situation, either case will work. In the case of MPIO, each disk will have one path through the lone HBA. However, management says one day we might do double HBA attachment, and the choice will be between MPIO and EMC Powerpath. Powerpath requires EMC.Symmetrix.fcp.rte, which cannot coexist with EMC.Symmetrix.fcp.MPIO.rte, as we have just seen. So, the possible scenarios are:

1. Configure now with MPIO and schedule down time if Powerpath is chosen
2. Configure now without MPIO, and schedule down time if MPIO is chosen

To me, choice 1 seems clear. Screw EMC!!