Tape Backup

Tape backup evolved, its performance and capacity being improved in an impressive manner. So, is tape backup dead? Not at all. Despite disk storage getting larger and cheaper, looks like tape will still be around for quite a while. And for long-term storage (archiving), tape backup remains the recommended strategy. Besides, tape backup has a small green footprint. That is to say that tape is greener than disk.

With the rapid advance of technology, when disk storage is becoming cheaper, and faster, is easy to get tempted to exclude the tape backup, and to implement an exclusively disk based backup solution. Disk to disk backup is ideal for short term storage, faster backup and rapid restores. With disk, the main focus is business continuity (BC) and disaster recovery (DR).

But there are also other requirements your data storage must meet. Data must be retained long-term through archiving, as required by the business profile and Data Retention policies, and compliance regulations. There may be other reasons to provide for a longer term data storage, keeping past data which is still used for business purposes, for example to identify trends.

Especially for long term storage, tape backup is the main choice:

• - It is greener, because it does not need energy until you want to read the data stored on tape.
• - Lower TCO (Total Cost of Ownership), calculated considering factors like maintenance, floor space, and training.
• - Tape is portable.

In essence, despite the enthusiastic opinions considering tape backup a thing of the past, the backup strategy should involve a combined solution of backup to disk and tape backup (D2D2T or Disk to Disk to Tape Backup).

• - D2D – designates the short-term storage part of the strategy, backing up data to disk for faster backups and restores.
• - D2T – designates the data backup targeting the long-term storage (archiving), and offsite storage.

In this architecture, the backup to disk (D2D) can be performed to a Virtual Tape Library (VTL). The VTL is reducing the disk storage size requirements, by performing Data Deduplication. The disk size reduction may vary, with vendors claiming compression rates between 10:1 to 100:1, thus considerably reducing the disk storage cost.

It is up to your company policy to decide for how long you need to keep data on the intermediary disk storage. The same stands for the long-term storage on tape. Also, you need to decide for how long you keep old tapes in the library for near-line, although slower, access, and when you actually take them out of the tape library for shelf or offsite storage.

Conclusion:

The decreasing costs of disk systems together with the increase in capacity, especially for second-tier SATA disks storage, does not provide such a substantial advantage to justify excluding the tape backup form your overall backup strategy.

Long term storage, especially for archiving purposes, is still favoring the tape backup. The energy consumption factor is also a strong reason to maintain tape backup in the company’s backup strategy.

Overall, the enterprise is in better shape if it continues to use tape libraries, and makes the tape backup part of a tiered storage strategy in a D2D2T architecture.