My web needs are simple. I use debian os, apache, mono+xsp+mod\_mono for aspx hosting, mysql, nagios, some bash scripts for backup purposes and occasionally random libs like encryptfs which i may not bother with to encrypt git repositories.

My question is, should i bother switching from VPS to amazon EC2? is it complicated? is it only worth it if i have a busy machine? and lastly

If i should then my question is...

What should i know before switching?
I assume a 2nd instance means i have an clone of my OS running. I dont know what happens if i save data on the local instance, is it mirrored? lost when shutdown? does writing to one instance show up on another since its a shared hdd? and what happens to mysql/how do i handle multiple instance accessing it?