All recovery points should be able to recovered with 0 errors. Constant confirming of backups is key to this strategy.
1 Copy Offsite
All mission and business critical applications should have at least one copy offsite. This ensures for a site disaster that data is available and protected from physical and logical corruption.
3 Copies of the Data
All data with SLA's should have at least 3 copies of data. This should include primary, secondary copy, and backup/virtual copy.
4 Copies of the Data
Mission Critical applications should be protect by four copies of the data. This includes primary, secondary, backup and backup copy.
2 Media Formats
The technology gap should not be based on media types, but instead media formats. This is on a premise that data should be protected in native (Ex: Server) and compressed format (Backup Software).