Okay since this qestion has been asked by many people, I'll try to provide what I Know. I can only tell you how to get this done, I don't have a working code because I don't have any EMC resource with me. I'll post one if I can get one.
1. For creating WFA commands for EMC systems: EMC may be providing apis, but I find the best thing to manage EMC systems is using EMC Storage Integrator for windows suite. It can be downloaded from https://support.emc.com/downloads/17404_Storage-Integrator-for-Windows-Suite . Storage Inegrator is UI management tool, but it also has a Powershell pack. Read the documentation on how to use it here: https://community.emc.com/servlet/JiveServlet/previewBody/17664-102-1-62790/EMC%20Storage%20Integrator%20PowerShell%20Toolkit.pdf
The latest 2 versions need Powershell 4.0 and .NET4.5
Another option is: EMC Storio Powershell toolkit. Read an download it from here: https://community.emc.com/docs/DOC-8561
But Storio has been since long time and not as powerful as ESI.
2. For Datasource acquisition: WFA support SQL based Datasource acquistion. So if there is some monitoring SW that monitors EMC systems and which exposes it DB login to external world, WFA can easily acquire it. OnCommand Insight I belive is a candidate here. There must be others from EMC too but I don't know about them.
If the managing SW doesn't expose its DB, WFA provides script based Datasource acquisition as well. You would need to create a DataSource type with method: script. So now you can use the ESI not only for command but getting all the required information from the EMC system directly. This mechanism is awesome except that if you have a large number of EMC systems then you'll need to add a Data Source of the particular Data Source Type for every EMC box. Not a big problem, but yes a problem.
Now after acquistion you create your filters etc.
That's all is needed to manage EMC using WFA.
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