BackBox H4.00 User Manual

Configuration
39 BackBox H4.00 User Manual
Number of virtual volumes
It is a good idea to avoid defining a lot more volumes than needed. Smaller catalogs
are easier to manage.
In addition, the free-up of expired storage is not possible in some environments; for
example because the tape catalog is not supported by BackPak, or because it was
not possible to write a delete script to free-up the back-end copy of an expired
volume in the Enterprise Backup infrastructure.
In such environments, the only way to limit the storage occupied by expired volumes
is to accelerate the re-use of an expired volume. The simplest way to do it is to limit
the total number of tape volumes.
Media type of virtual volumes
There is no media type, such as LTO3 or LTO4, permanently associated to each
virtual volume in the BackPak catalog. Each volume is considered of the media type
currently defined in the corresponding Volume Group.
But there are some constraints related to the media type:
• Each tape drive reports a media type to NonStop host queries.
• DSM/TC (but not TMF) associates a media type to each catalogued volume.
When the DSM/TC volume is requested, it will load only on media type
compatible tape drives.
• Some features are available only on specific tape drive types. For example, when
the volume encryption is implemented through HP VLE, only LTO 4 tape drives
are supported.
BackBox VTC can emulate these media types:
• CART3480
• LTO2 (on LTO 3 tape drives)
• LTO3 (also on LTO 4 tape drives)
• LTO4