VTLs

VTL stands for Virtual Tape Library. It is a storage system that emulates a physical tape library using disk-based storage. VTLs provide many of the benefits of tape storage, such as data archiving and disaster recovery, but with the performance advantages of disk.

The core concept of a VTL is to present a disk array to a backup application as if it were a physical tape device, such as a tape drive or a tape changer. This allows organizations to leverage their existing tape backup software and infrastructure without needing to replace it entirely. When data is written to the VTL, it is stored on disk. However, the backup application sees it as if it were being written to a tape.

VTLs offer several advantages. They provide much faster backup and restore times compared to physical tape libraries due to the inherent speed of disk access. They also reduce the need for manual tape handling and management, which can be labor-intensive and prone to error. Additionally, VTLs can be integrated with de-duplication and compression technologies to further reduce storage space requirements and lower costs.

However, VTLs are not a direct replacement for all tape use cases. While they excel at providing fast access to recent backups, long-term archiving might still be more cost-effective with physical tape, especially for compliance requirements where data must be immutably stored offline. Many VTL solutions offer a hybrid approach, where data can be migrated from disk to physical tape for long-term retention.