Virtual TapeServer 6.04.03 Operations and Administration Guide

56 | Managing Pools and Virtual Tapes
Managing virtual tapes
You must create a virtual tape before the host server can mount and write data to it. When
you create a virtual tape, a file is created on the VTS server’s disk. The file is empty except for
up to 27MB of header information (metadata), which is used by VTS to retain an audit trail of
information, including the following:
• Tape label information, such as the volume label
• When the virtual tape was created, written to, updated, mounted, unmounted, or erased
• If and when the virtual tape was exported, imported, migrated, or restored
• How long the virtual tape has been retained
• The ID of the key used to encrypt the tape, if SecureVTS is enabled and the tape is
encrypted
The following procedures describe how to set properties for virtual tapes and perform common
tasks such as creating, erasing, and exporting virtual tapes.
Enabling data compression
You can configure VTS to compress data before it is stored on virtual tapes. By default, this
option is disabled. As data is transmitted from the host server to VTS, VTS compresses the
data. Typically, the compression rate is at least 2:1. This saves disk space, improves
performance, and reduces CPU use.
Requires the Edit Configuration File access rights
To enable compression
1. Click Supervisor Functions on the navigation pane.
2. Click Enable Compression.
You can see the compression ratio for each virtual tape on the Virtual Media - Operation page,
in the c/ratio column. The compression ratio is read when a virtual tape is unmounted.
Note If the c/ratio column is not displayed, see Enabling features on the web interface on
page 47 for information about displaying the column.