Yes, just cause it has RAID 5 doesn't mean the processor can't die (happened), or the RAID card in the data center you've never been in can't die (happened), or an unclean shutdown of a VM causes your sparse LVM Volume to die (happened)....

Back up your stuff. Probably good to have two servers and have backup versions of your service ready to go on there in event of a disaster + a place to restore your S3 backups in to.