I've ran into a number of different scenarios lately around xDB and data retention and archiving.
What is the best practice for archiving data in xDB in general? For example, is there a best practice for how long to keep anonymous data? By archiving or outright deleting that data, rebuilding the reporting database will no longer give full historic data, right?
For PHI environments that require 8-10 years of data retention, what is the best practice for archiving that data? Another Mongo instance? Encrypted to disk? How is this accomplished?