I recently helped a Fortune 100 client evaluate continuous data protection (CDP) products and was asked if full nightly backups to tape were still needed given the advent of disk-based technologies like snapshots and CDP. Trying not to sound like a consultant attempting to please everyone, I answered "It depends."

Snapshots and CDP provide excellent ways to recover data from a specific point in time when no known data loss or corruption existed. But it can take a while to discover a file or database error, and snapshots aren't typically kept for a long time. That's why full backups to tape are a vital complement to point-in-time backup tools, and will remain so in any comprehensive data protection strategy. The tricky part is to decide how to mix and match backup methods to best meet recovery time objectives (RTOs) and recovery point objectives (RPOs), and stay within your storage budget.