Virtual TapeServer 6.04.01 Operations and Administration Guide

Introduction | 3
Overview of features
The following VTS features enable you to simplify and streamline tape operations, reduce
costs for storage, automate backup and restore operations, and increase flexibility in
managing backed-up data:
• Flexible and extendable, enabling you to create any number of virtual tape pools that
“contain” any number of virtual tapes
• Compatibility with Backup, Restore, and TMF
• Compatibility with Mediacom and DSM/TC
• Support for backup management applications, including IBM Tivoli Storage Manager,
Symantec Veritas NetBackup, Syncsort Backup Express, and EMC Legato Networker
The heart of VTS is a middleware tape emulation engine that enables VTS to emulate tape
storage to host servers and provides backup storage for the data on industry standard, low-
cost disk arrays. Data stored in VTS can later be copied to real tape media for archival storage
or disaster recovery if long-term backup copies are required. The advantages of this approach
include the following:
• Access to data in VTS is almost immediate, and there is no tape to mount or rewind and
no searching through tape volumes for data files.
• If additional tape storage is needed, you can create virtual tapes using the VTS web
interface without involving the host server. Tapes exported by VTS are identical to those
made by the application directly and can be read on any NonStop server, including sites
without VTS.
• VTS allows multiple hosts to perform up to 32 simultaneous backups per VTS server. Up
to one virtual tape drive (VTD) is supported per SCSI bus, up to four VTDs are supported
per Fibre Channel port, and up to 32 VTDs are supported per VTS server.
• Data compression — Allows VTS to compress files as they are written to disk storage
devices. Its use can double the available storage capacity and reduce the amount of
associated storage costs. This feature uses an “on-the-fly” compression algorithm that
creates little processor overhead and can increase performance and throughput by
decreasing the volume of data written to disk.
Optional features that further enhance the benefits of VTS include the following:
• Global File System (GFS) support — Offers enhanced access to shared vaults and
eliminates single points of failure by deploying multiple VTS systems into a set of
clustered nodes. In the event of a failure, GFS enables any active VTS system in the
cluster to have access to the data, ensuring uninterrupted service to host systems.
• AutoCopy and Instant DR — Enables the creation of a disaster recovery plan by
efficiently copying or synchronizing backup data between a local VTS server and one or
more remote VTS sites. These features allow for maintaining one or more copies of backup
data at a remote site. AutoCopy automatically copies a virtual tape from one VTS system
to another when the virtual tape is mounted, modified, and dismounted by the host
server. Instant DR uses a delta-difference engine to identify data on a virtual tape that
has changed from one backup to the next. After the initial backup is copied to one or more
remote locations, only that portion of the backup data that has changed since the last
backup is transmitted from the local site to the remote site.