Hi,
Although I haven't used the e-series much, previous experience with this platform (oem rebranded by IBM) I was able to poll the management host where the santricity client was installed. You will need to keep the client running all the time, but works reasonably reliably. SNMP alarms will typically be triggered if the santricity client fails, providing some assurance that you will always have reliable monitoring in place.
Please post any further feedback you have, I may be deploying Eseries soon so would appreciate any tips on SNMP monitoring specific to this (eg if you have access to the MIBs). Additionally, feel free to reach out to me with any specific questions whilst you're configuring and I'd be glad to assist where I can.