Contents |
What is virtual tape?
Virtual tape was invented to address the problems associated with underutilized tape library cartridge capacities. By using disk arrays as a front end "cache" to a tape library, virtual tape systems allow the placement of many more tape volumes on a cartridge, thereby dramatically increasing utilization. Access activity determines which volumes are stored in the disk array buffer and which are migrated to physical tape. The image of the device appears to the operating system as a tape library, thus virtualizing the system.
Business impact
This approach has several benefits including greater flexibility, as the number of virtual tape devices can exceed physical drives, performance as the disk buffer can be used for more frequently accessed data and accelerated recovery times. This results in dramatically reduced costs in many applications and reduced business risk as recovery times are improved.
How does it work?
Virtual tape packages disk arrays with direct I/O to attached servers along with tape libraries to present a tape library image to the operating system. The disk arrays appear as a virtual tape device image. Data movement and migration is managed by policy-based software that places data based on access patterns and frequency of use.