Ephemeral give you extremely high IOPS for no additional cost. It's perfect if you don't need a ton of disk space. A great example is Graphite. Very high IOPS r

Ephemeral give you extremely high IOPS for no additional cost. It's perfect if you don't need a ton of disk space. A great example is Graphite. Very high IOPS requirement but (usually) a low disk space requirement (assuming you configure relatively low retention) The c3.2xlarge boxes are great for that. The equivalent on EBS on the other hand will cost you an extra $250/mo or so in addition to your server cost. And you will cap out at 4000 IOPS.