For decades, tape users have struggled with shrinking backup windows, escalating backup costs, poor reliability of backup systems, backup/restore (B/R) performance issues, cumbersome recovery and high labor costs associated with backup and restore. Disk-to-disk (D2D) backup technologies such as virtual tape promise to address many of these problems. However, in a storm of acronyms, overlapping functionality and vendor marketing the right strategy is not always obvious.
On the spectrum of data protection choices, virtual tape fits somewhere between conventional tape and snapshot copy/replication. This spectrum is large and growing, spanning out through continuous data protection (CDP), asynchronous and synchronous replication all the way to 3-node disaster recovery. Most solutions in this spectrum still largely rely on tape for the final archiving solution.
In the near term, successful disk-to-disk backup approaches including virtual tape will leverage existing BUR practices that have been hardened over the years, mainly using sequential tape approaches. Applying D2D technologies means evaluating the following:
- What are the RPO/RTO requirements of an application and how much data loss is acceptable?
- What is the backup window?
- How will existing tape/backup processes be leveraged?
- What is the reduction in expected loss?
- What is the budget?
While the answers to these questions will begin to help formulate a strategy to implement D2D backup and choose the right solution, trade-offs must be understood and fully vetted. For example, if implemented in virtual tape, how will de-dupe and/or encryption impact recovery times? What are the compliance implications of reducing tape usage and how should tape media and device strategies change as a result of using D2D solutions? Simply throwing tape out won't cut it with the auditors.
Action Item: Users must carefully evaluate which practices in B/R are and are not effective and use virtual tape (and other D2D solutions) to make adjustments at the margin as to how backup and restore technologies are introduced into the labor pool.
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