Amazon EBS caveat

When running your EC2 instances on the Amazon cloud with EBS volumes attached you should be aware that mounting EBS volumnes on Linux mount points /dev/sd[a-e]can lead to that the writes to the mounted EBS volume will not be flushed in case of a hardware failure.

You can read more about How to Attach the Volume to an Instance but most important is Instance Storage. 

In order to ensure that all your data intended to be written to the EBS volumes is indeed written to them and not the instance's local ephemeral storage, you should only use device names in the range /dev/sd[f-p].  More information on recommended device names can be found here