How to check FE,BE and RDF Director's performance in VMAX

You can use Symstat command to check the performance statistics:

To display statistics about all RDF directors in the specified Symmetrix array every 60 seconds for a count of 10, enter:

   symstat ‑i 60 ‑c 10 ‑RA ALL ‑sid xxx

To display REQUEST statistics about all front‑end SA directors in the specified Symmetrix every 10 seconds 100 times, enter: 

    symstat ‑SA ALL ‑i 10 ‑c 100 ‑type REQ ‑sid xxx

To display BACKEND statistics for device 068 on the specified Symmetrix every 10 seconds, enter:

    symstat ‑i 10 ‑type backend ‑dev 68 ‑sid 8910

For more command syntax of symstat, please refere Solutions-Enabler-Symmetrix-CLI-x.x-Command-Reference on support.emc.com

BTW, your question written to the users' own "Discussions" space don't get the same amount of attention and questions can go unanswered for a long time, You can select "Move" under ACTIONS along the upper-right.  Then search for and select: "Symmetrix Support Forum" which would be the most relevant for this question.