There is a similar thread for isilon firmware 22.214.171.124. We've found that monitoring is spotty or totally dead on moving up to the 9.1 firmware. Support have told me a feature request is the way to go.
The problem shown is that either some of the polls do not complete regularly, or that the whole array becomes unreachable
I'm partway through writing a custom solution while the devs get to the OOTB one. Has anyone got further than me and have a working API poller template or SAM monitor or a scheduled task or a stored procedure or whatever else?