MongoDB vs. Redis vs. Cassandra for a fast-write, temporary row storage solution

Question

I\'m building a system that tracks and verifies ad impressions and clicks. This means that there are a lot of insert commands (about 90/second average, peaking at 250) and some

Answer 1

I currently work for a very large ad network and we write to flat files :)

I'm personally a Mongo fan, but frankly, Redis and Cassandra are unlikely to perform either better or worse. I mean, all you're doing is throwing stuff into memory and then flushing to disk in the background (both Mongo and Redis do this).

If you're looking for blazing fast speed, the other option is to keep several impressions in local memory and then flush them disk every minute or so. Of course, this is basically what Mongo and Redis do for you. Not a real compelling reason to move.