The MIM Portal scan collects data from a MIM or FIM Portal database. There is a full scan version of the step and delta version. The primary difference is that the delta version only inspects objects that have been targeted by a request since the last scan.
In the case of both scan types the data collection will query the Identity Panel history API to determine when the last scan was performed and limit collection of request objects to those newer than the last scan.
Because a full scan of the MIM portal needs to enumerate the entire database, particularly large volumes of text and reference attributes it should be scheduled for periods of relatively low portal activity, as the scan SQL query volume can actually have a small impact on portal page load performance.
Both Portal scan step types have a required Environment parameter.
The non-delta portal scan has an optional "Limit Request Volume" parameter. If set to 0 no limit will be place on request volume.
This parameter is most useful for the initial load scan of a large portal environment with a very active request history (as might be found shortly after an initial deployment of MIM. If the environment has hundreds of thousands or even millions of requests in the 30 day (by default) history queue, the initial load scan may consume tens of gigabytes of RAM as it caches those requests to parse out change history.
Setting the limit requests parameter forces the scan to only consider the most recent requests up to the limit specified.