Everyday I generate about 500.000 XML documents with about 12kB each one, totaling approximately 6GB per day. I need to store these documents the way I can retrieve it entirely with a key or a file name. There is no need of scan the content of files, just retrieve them with respective key or name.
Which is the best engine to this task?
I would like to hear opinions with no consideration of limitations but also opinions considering low cost with free software.