May not be as durable as EBS, but it's enough for me to sleep soundly at night. And with a highly concurrent WAL-G download, it takes like an hour to catch up a new replica from scratch.
Netflix went full ephemeral storage for their Cassandra clusters since the beginning, at the time when they were just spinning disks. Years later, they still insist on doing this, and had to come up with creative solution to fix the uptime issue: https://netflixtechblog.medium.com/datastore-flash-upgrades-...
> it takes like an hour to catch up a new replica from scratch
That means it should be pretty easy to replace an instance - just create a new replica from scratch, then fail over (if you're replacing the current master/primary instance), and remove the old one.
Anyway, from the other comment here, I think tommyzli might not have realized that a reboot is still possible, which would partially explain the 3 years uptime.