Backup To A Shared Virtual Library - HP 12000 Design Manual

to their own dedicated virtual libraries. During the echo copy window, all the virtual cartridges
from the virtual libraries are automatically and transparently copied to the single physical tape
library. This scheme provides daily off-site protection and archiving of the physical tapes.
The user can configure additional virtual slots in the virtual libraries. That is, there can be more
virtual slots than the number of physical slots mapped to the virtual library, to provide spare slots
for restore from disk. These additional slots in the virtual library can also be used to contain purely
virtual media (for example, media that has no mapping to any physical tape). The user can then
create a separate media pool for the purely virtual cartridges, so that not all backups go to physical
tape. For example, the user can direct full backups to the media pool containing the automigration
virtual cartridges, and incremental backups to the purely virtual media. Thus, only full backups are
going to physical tape. An alternative to this would be to create a separate virtual library for
incremental backups which would contain purely virtual cartridges.

Backup to a Shared Virtual Library

In this use case, the customer has multiple backup hosts on the SAN fabric that are sharing a single
virtual library on the VLS device. This is the normal configuration for the majority of enterprise
customers. Even though this shared library configuration allows tape copying via the backup
application, some customers still wish to use automigration to reduce the licensing costs of the
backup application or remove copy data from their SAN. See
Figure 39 Shared Virtual Library
In this scenario, there is one or more physical tape libraries that need to be mapped to a single,
shared virtual library. The physical library or libraries can be bigger or smaller than the available
disk space on the virtual library. If the physical library has more capacity than the available disk
of the virtual library, only a subset of its slot range is assigned to the virtual library. This allows
multiple backup servers to backup to the shared virtual library, and then during the copy window,
all the virtual cartridges from the virtual library are automatically and transparently copied to the
one or more physical tape libraries mapped to that virtual library. This scheme therefore provides
daily off-site protection of the physical tapes.
84 Automigration
Figure 39 (page 84).