YES. We have a strict no-EBS policy. Our main concern is that historically EBS has been a big single point of failure that can take down an entire AZ or worse a whole region. There were a number of outages in 2010-2012 that really bad for EBS instances[1][2]. The rate of outages has certainly gone down since then, but its hard to trust a system that has burned you badly multiple times in the past.

There was a good post by Bryan Cantrill after one of those really bad outages[3]. While this post is from an AWS competitor, the arguments about the reliability of network storage are sound.

While the trend by AWS has been to move away from ephemeral storage, it doesn't seem like they are working to completely kill it off. d2 and i2 fill a lot of our storage node needs. For our compute nodes I could see us moving to a model of booting off ebs and then pivot rooting into a ramdisk root fs so nothing would touch ebs after boot.

[1]: https://aws.amazon.com/message/67457/ [2]: http://www.agilesysadmin.net/ec2-outage-lessons [3]: https://www.joyent.com/blog/on-cascading-failures-and-amazon...