[smoody]

At the risk of sounding both lazy and naive, if i want to utlize replica sets, do i have to separate each mongodb instance onto a separate hardware box? put another way, if i want to deploy a durable mongodb installation, do i need three or four EC2 instances (for example) running at the same time, all the time?

[anto1ne]

yes you do. and not only on production. if your dev box with mongo is rebooted unexpectedly, there goes your data.. you'll have to do a db.repairDatabase() or restore completely, which can take hours if you have a lot of data.