Distributed Key Stores: Roll your own!
By searchguy on Apr 21, 2009
The really interesting part of this though, is that he had a look at a lot of the available options (admittedly on a pretty tight schedule) and his conclusion is that, given the maturity of the options available you could probably write your own in a day.
I'm pretty interested in retrying some of this evaluation with our own data. I'm not sure how the numbers will compare given that we're doing inverted indexing on the text in the items that we're storing, but it will be interesting to find out!