Assumptions -
1. Considering you FAS2020 currently not having any disk shelf connected.
2. FAS2020 is dual controller system
3. You have 1 FC port free for shelf connectivity
4. Free FC port on FAS2020 is in Initiator mode
Steps -
1. Rack mount disk shelf
2. Power on disk shelf
3. Check and verify all HDDs, power supplies and other components are green
4. Connect SFP modules in disk shelf ESH4 FC ports (In and Out)
5. Take LC-LC FC cables and connect between onboard FC ports and In port on disk shelves (one from each controller to ESH modules)
6. Check disk visibility to controllers by running disk show -n and then assign the disks to respective controller
7. Create required Aggregates --> Volumes
If you have existing DS14MK4 FC disk shelf, then you can add the new disk shelf in existing loop. You will need to power on new shelf and then connect FC cables from out port of last shelf in existing loop to in port of new shelf. You can have maximum 6 shelves per loop (best practices 4 )
Hope this helps...