When upgrading from a FlashArray//X to a FlashArray//XL, the hardware migration often involves handling DirectMemory Modules (DMMs) differently than standard data drives. DMMs are high-performance cache modules that reside in the controller chassis.
In this specific scenario-migrating a fully populated //X90R3 to an //XL that already has its own set of DirectFlash Modules (DFM-Ds)-the DMMs from the old chassis need to be moved to the new chassis to preserve their cache function or be properly decommissioned.
The correct procedure is to Evacuate DMMs as a datapack then install into any slot in //XL.
DMMs cannot be simply "hot-swapped" randomly while the system is live in a way that disrupts the cache map.
They must be logically grouped and evacuated (conceptually "vacated" of active data) so they can be safely removed from the old chassis.
Once removed, they can be installed into the new //XL chassis. The //XL architecture supports DMMs in specific slots, and Purity will detect and re-incorporate them into the cache pool.
This ensures that the expensive SCM (Storage Class Memory) hardware is reused in the new system without causing data integrity issues during the transition.
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