I would like to have some suggestion for choosing the right database for my system. I am dealing here with multimedia data (images, video, audio, motion, ...) and should be having a high number of users accessing my database e.g. 50000 users.
The data is collected from other storage devices in real-time, which should be expandable as well as the number of users getting access to the system.
First thoughts were to use a no-SQL database e.g. RIAK or Cassandra for being expandable but I am not sure if using a multimedia database would be better in this case. And I have actually no experience using no-SQL databases.
Ideally you want a solution that can scale-out.
To maintain a responsive solution for the growing number of end users as well as increasing content, you want to be able to add systems and distribute the load as well as content across systems without taking the systems off line.
A distributed nosql solution should work well. It can hold the meta data about the content. Anything that is not searched/compared against a query, e.g. audio, video, images, etc. should go in files.
Nosql typically has relatively better lookup performance. I.e. given a key, lookup the value. If your app has queries which are not simple lookup, then SQL may be better.