Note that you can only get up to 7 usable members in a RS (then you need to shard), see http://www.mongodb.org/display/DOCS/Replica+Sets+Limits http://www.mongo

Note that you can only get up to 7 usable members in a RS (then you need to shard), see http://www.mongodb.org/display/DOCS/Replica+Sets+Limits http://www.mongodb.org/display/DOCS/Replica+Sets+Limits I'm curious if you happen to use any monitoring to notice when load on your mongo servers gets too high (eg is about to start swapping to disk instead of using RAM etc)? Cheers