removing old ODM before upgrading to latest

the readme file for ODM 5.3.0.4 states:

Symmetrix Support:
-----------------
If you are running AIX 5.2 and EMC ODM Package 5.0.0.0 or 5.0.0.1,
you must remove them before installing this version.
If you are running EMC ODM package 5.1.0.0 or 5.2.0.0 and higher, 
then proceed with the upgrade. 

so do we still need to remove ODM if we are on 5.1.x and higher ?

Thanks

so simply upgrading ODM does not update fileset ?  What does it do then ?  Removing and reconfiguring devices from ODM is a lot more intrusive and i would like to avoid that if it's un-necessary.

When you update the filesets, it does not apply to the disks that are already recognized, their specifications are already populated on the ODM.

The ODM is populated as the disks are recognized based on the filesets that are in place at the moment. 

Read me is talking about upgrade the filesets.

The primus emc144935 is talking about removing all the disks (clean up the ODM), upgrade the filesets, than recognize the disks again, so all disks will have the specifications of the new filesets.

i see. Can you give an example when one would want to go through the route mentioned in the primus versus simply upgrading ODM  without messing with existing definitions. We are not changing device types (like converting STD to RDF1).

Thank you

I would say that the best practice is always follow the primus.

Lets say that you are at a version of ODM supported, but you are going to upgrade it.

If you don't clean the actual devices and add new devices, you would have devices recognized with two different filesets, so they can have specifications slightly different.

There some situations that it will be mandatory follow the primus, remove all the devices and reconfig them again with the new filesets.

Imagine that certain version PP requieres a new version of ODM, if do not remove the actual devices, they will keep the specifications of the old filesets even after the upgrade of them.

So following the primus is the only way to populate the ODM with the new filesets specifications and be sure that all EMC devices are running the with the same specifications.