In SSRS, I noticed that the rdl.data cache files are being stored on my dev machine. Are these files also stored on the Reports Server when reports are run? If so, is there a way to avoid creating those files on the server?
rdl.data files aren't created on the server - they're purely to speed up report execution time during development when you repeatedly run the report with the same parameters whilst tweaking the layout.
As a side point, I believe it's true to say that it's possible to configure the SSRS service to cache results for reuse.
I don't know the details of the caching mechanism that the service uses; it might use a file-based mechanism like rdl.data, or it might store the results in one of the ReportingServices databases.
Perhaps someone more knowledgable about SSRS can confirm the details of the mechanism.