In Performance Management (PM) what is the difference between a Group and a Collection?
A Collection is a "Monitored Group" on the Data Aggregator. It is a flat (no nesting of Collections) collection of devices that are used for applying monitoring configurations. Monitoring Profiles and Event Profiles can only be applied to a monitored group.
A group is used for grouping items into various structures for the purposes of reporting in Performance Center. Monitoring Profiles and Event Profiles can NOT be applied to groups.