Dell NetWorker 19.9 Administration Guide

Cloning with tape devices

There are a number of reasons why tape devices are used as part of the cloning process:

• In cases where tape is used as a secondary storage tier where selected data is cloned to tape for offsite storage or for extended data retention periods. This allows disk devices to be used for the initial backup where their speed and flexibility can be most effectively used for fast backup and recovery performance.
• In cases where tape is used as the primary backup media, there are still benefits in creating clone copies, including:
  • Secondary copy at different location or for offsite storage.
  • Data validation.
  • Verification of the ability to read data from the media.
  • Added protection of multiple copies across multiple volumes.
  • De-multiplexing of multiplex backups for faster recovery.

Cloning with tape devices provides two benefits which should be considered for every clone:

• Unlike disk-based devices, tape devices read data in a serial format. This means that while multiplexing is beneficial from a backup streaming perspective, this is not the case for recovery.
• If recovery speed is important, the use of clone copies as the source is likely to result in faster recovery throughput.

Tape clone copies are often the preferred method to read data in a disaster recovery situation. The ability to acquire, install, and configure a tape unit to read data is often the first task on a disaster recovery plan.

By creating a copy of the backup on tape, you can eliminate the need for appliances such as VTLs or disk systems to be in place. This often takes longer to acquire, install, and configure. However, ensure that the tape copy is a full and complete copy, without the dependence on other backups or deduplication appliances to complete the restore operation.