Comment by pjungwir

I've been intrigued by the idea of running databases on EC2 instance storage for a long time. (You couldn't use RDS though, at least not today.) Putting your db on something also called "ephemeral storage" seems risky, but maybe not much riskier than putting it on plain HDDs. The big issue to me is that most instances don't come with much space. If you need more you have to scale up the whole instance (not a separate dimension like with EBS), and if you're already on the biggest instance type you're just out of luck. I guess it could be worthwhile to use separate tablespaces so you could have some data on instance storage and some on EBS. But so far I've gotten acceptable perf by RAIDing over gp2 EBS volumes (12 TB in my case), following the approach here: https://news.ycombinator.com/item?id=13842044