do you have dr vfiler on this system? if yes, this shoud be because DR vfilers are added with the same object ids as the source vfilers. OCPM ceases to poll volume data on the filer or vfilers because of this.
try below steps:
1. Remove all storage controllers managed via SCOM using OCPM. 2. Add either the primary OR secondary controllers, the production and DR systems cannot exist together in SCOM at this time. 3. Check volume data and confirm that counters are now displayed appropriately.
Frank, it's been a while but in case you or anyone else is still having this issue... I had the same problem and resolved it by righ-clicking the "Volumes" object, clicking "Personalize View", and then clicking "Reset to Default".