what is meant by SAN IOP numbers of drives ?

that's kind of a loaded question. You have physical drives that can so many iops

15k - 180 iops

10k - 130 iops

7200 - 80 iops

these are for random, small block workload. Now you also have a lot of cache in DMX/VMAX arrays that will make a lot of random workload appear as sequential and give you even more iops from those drives. If your array is already in production and you want to collect performance numbers, you have a couple of options:

SMC/SPA

Performance Manager (part of ECC infrastructure)

Solutions Enabler (symcli commands and stor daemons)

some of these will provide historical data, some current only.