Hi CrashCart,

This method should work https://dell.to/3id3GuT

Thanks for that link.  A quick glance through it makes it look fairly straightforward and doable.  (I will of course take a little more time to re-read it and think carefully about the steps before doing anything)

One more follow-up question:  

We tier off older data to an ECS unit.  Is it possible to do a migration to a new Isilon without first having to recall all that data first?

(If there was official documentation that covers the different scenarios it would be helpful for evaluation/planning)  

There is a guide, https://dell.to/33FlDhw

The second link you shared does not really address the (older) data that has already been tiered-off to the ECS.  Nor does it address the snapshots from the existing Isilon. I suppose that if we proceed, we will have to live with re-hydrating all that is currently stored on the ECS.

(I think the idea from that first link you shared should be able to preserve the snapshots, but even that is just a little bit scary)