MongoDB works very well for us with 100GB of data per collection, although we did run into a severe bug with .count not using an index, totally killing performa

MongoDB works very well for us with 100GB of data per collection, although we did run into a severe bug with .count not using an index, totally killing performance (we're talking 60 seconds to return). Inserts and indices, however are very very fast, and the bug was fixed incredibly quickly and now works in trunk. It doesn't seem quite cooked yet, but it's a very very nice start, and promises much. I prefer it to the other KV stores that are out there right now, anyway.