Every day of the week, your entire account is backed up and stored on the main server. These backups are kept for 5 days, and if something went wrong before the 5 days, there's a monthly restore point to fall back to.
All our servers are equipped with RAID 10 (Stripe+Mirror), to provide fail-over and performance.
Our entire server is backed up daily to provide fast recovery, in case the unthinkable happens.
Backup sets are transferred to our dedicated backup server daily, just to make sure.