Virtual TapeServer 8.2 Configuration Guide

Introduction | 3
needed, it can be discarded just like a physical tape. A virtual tape is synonymous with a file
in a directory.
Overview of features
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. A tape that is individually exported using
tape-to-tape export by VTS is identical to one made by the host application directly and
can be read on any host server, including sites without VTS.
• Dynamic Data Reduction, which allows VTS to compress files as they are written to disk
storage devices. Its use can provide up to 12 times 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.
• Tape-to-Tape Export, which enables you to export data on a virtual tape to a physical tape
in an external tape drive or library. This provides a one-to-one mapping of virtual to
physical tape. When creating the tape-to-tape export job, you can choose whether the data
remains in virtual tape format or host format. This allows application-aware exports
because you have the ability to name the virtual tapes such that they are the same as a
pool of physical tape cartridges. This then ensures that DR reports created by backup
applications are accurate when a virtual tape has been written to physical tape.
• Dynamic Import provides the ability to dynamically import data from pre-existing
physical tapes in a physical tape device. This enables you to use older tape formats and
restore them to a host. Or, you can convert older physical tapes by importing them and
then exporting the virtual tapes to newer physical tapes. For example, you can import
DLT7000 tapes into VTS; when you import physical tapes, the data on those tapes is
stored on virtual tapes. Then, to convert the data to LTO-4 format, you could mount each
virtual tapes in a VTD that emulates an IBM TD4 drive and restore them to a host.
• Scan/Cleanup, which enables VTS to scan pools and virtual tapes to identify virtual tapes
that are past their retention period. Scan/Cleanup can erase old virtual tapes to recover
disk space. You can also schedule virtual tape erasures when the overall disk space falls
below a specified threshold. Finally, Scan/Cleanup can erase tapes after they are exported
to physical tape.
The following VTS features enable you to simplify and streamline tape operations from the
host server, 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 TMF Backup and Restore
• Compatibility with Mediacom and DSM/TC
• Support for migration through the use of backup management applications