Disaster recovery Toolkit

Reliance on tape: A disaster waiting to happen

Mike Talon Tech Republic

Published: 05 Jul 2005 12:20 BST

In many companies, there's a distinct difference between a company's ideal business continuity strategy and how those plans play out in reality. One of the most prevalent disaster-recovery (DR) myths is the belief that tape backups are a sufficient DR solution for most companies. While some organisations can indeed rely on a tape-based system for their recovery needs, those businesses are few and far between. A corollary to this myth is some companies' belief that once they've performed tape backups, they're free and clear. But unfortunately, many organisations use tape backups ineffectively at best and improperly at worst.

Companies should use a recovery point objective (RPO) to determine how much data they can potentially lose during any given disaster. For example, if users update data in a real-time application (such as a Web-based purchasing system), your RPO should be as close to zero as possible (within the limitations of your systems). But if these systems save data infrequently (such as a file server used mostly for read-only files), your RPO can be 24 hours or more.

If your RPO really is 24 hours or more, your organisation can potentially use tape backup as its sole DR solution. However, it's imperative that you follow best practices, including moving tapes off-site on a regular basis and performing test restorations from the tapes to ensure data integrity.

If your company's RPO is less than 24 hours, don't rely on tape as your sole DR solution. It's too risky to depend on a tape backup that more than likely occurs just once a day; if a system goes down before the backup window, you could easily lose an entire day's worth of data.

Instead of tape backups, begin investigating data replication solutions. Available for a great range of prices, these tools generally offer the ability to fail over to other servers and perform additional tasks.

The closer your RPO gets to zero data loss, the more expensive your DR solution is likely to become. Keep in mind that solutions that ensure absolutely zero data loss nearly always require large-scale disk-based storage arrays and much more bandwidth than other types of data-protection systems. However, bumping up an RPO to anywhere from a few minutes to several hours can expand your options dramatically.

It's vital that your organisation recognises and understands both the benefits and the risks of using only tape backup as a DR solution. Relying solely on tape backups, particularly if you're not using them effectively, can give your business a false sense of security about its disaster recovery strategy.