Depends on how many systems you are managing, how many different matrix and reports you have to run every day/week/month, there will be different ways to do that. If you only have a handful systems, just use the cmdlets (Get-NcAggr, Get-NcAggrSpace, Get-NcVol, etc.) and script them to put them together like recomemnded in the thread. If you have more systems and need to run the reports frequently, and unlucky enough , have to put them together with other storage platforms ( IBM,Tintri, PureStorage, etc.) for Capacity Report monthly, then you might want to think differently.
I ended up with this hard way since I have 70+ NetApp systems, and others platform as mentioned above.
1. Use DataONTAP cmdlets to get all info for basic objects ( Aggr, Vol, LUN, etc.), output them into csv files
2. Import the csv files into an database ( MS SQL, MySQL, etc.) with tables pre-created based on cmdlet output preperty list
3. Create reports(database views) based on all of the info collected in step 1 in database, and optional publish them on Web GUI
4. Automate step 1-3 with cron jobs or task schedulers or SQL jobs, etc.
In this case, once you have aggr info and volume info, it will be just a join in database to get the Allocated info ( Total of VolumeSpace) per aggr or per controller or per facility, etc. Moreover, you will be able to get more and more reports based on queries and joins.( I have about 100 reports just for NetApp FAS/e-Series, and all are available in database anytime based on daily refresh for each system.) Attached is a sample capacity report for one cluster.
-Timothy