[piramida]

It is not mentioned in the docs, but not only EBS performance is unreliable, but it is also not uncommon to get a "stuck" EBS volume, where no I/O operations go through at all. So you have to a) monitor and be ready to take action on "dead" hosts stuck on IO and b) not completely rely on EBS as perfect (it is possible to recover data, in most cases, but it is much easier if you can just create a new one and kill the misbehaving volume, automatically).

So in case of running custom data-intensive setup you could: 1. create a RAID out of several EBS volumes, maintain that - predictable speed, much better reliability 2. easier if you need a small scale solution - regular ebs snapshots and be ready to lose some inbetween snapshot data. Also, I think performance of disk is not a big issue in MongoDB case, so case 2 might be enough for your application. EBS failures are rare, afterall, so unless your data is critical and there is no way to do replication, snapshots would do.