Are there ways to verify / quantify the rate of random or sequential access on Luns through tools Netapp?
The best way to do this is via your application. Databases are quite easy to determine the random vs sequential workloads using the built-in tools. Other applications may be more difficult.
Sequential workloads are handled very easily. However, random workloads are a bit more problematic.
To help you better, it would be good to know the application and what, if any, problem you are wanting to solve.