I have an EC2 instance running mongo, with data stored on a separate EBS device.
I decided to change EC2 instance type, and when I restarted I did not see the disk anymore, so I had to mount again. Don't know if this is due to instance downgrade, or if my mount simple does not survive the instance restart.
I mounted the disk with this command:
mount /dev/xvdf /data -o noatime -o noadirtime