HP B6960-90078 - Manual (Page 77)

Configuring and Using Backup Devices
Shared Devices in the SAN Environment
Chapter 2 47
Direct Library Access Concept
With direct library access, every system sends control commands directly
to the library robotics. Therefore, a system does not depend on any other
system in order to function.
With direct library access , when multiple systems send commands to the
same library, the sequence of such communication has to be coordinated.
Therefore, every library definition is associated by default with a host
controlling the library robotics. If another host requests that a medium
be moved, Data Protector will first access the system specified in the
library definition for performing the move. If the system is not available,
direct access from the local host to the library robotics is used if the
libtab file is set. All of this is done in a transparent manner within Data
Protector.
Indirect Library Access Concept
With indirect library access, only one system (the default robotics control
system) sends robotic control commands that are initiated from Data
Protector. Any other system that requests a robotics function forwards
the request to the robotics control system, which then sends the actual
command to the robotics. This is the default setting, and is done in a
transparent manner within Data Protector for all requests from Data
Protector.
Configuration Overview
This section provides an overview of the steps involved in configuring
your system. It includes the following topics:
• Configuration goals
This section specifies the mixed SAN environment to be configured.
• Configuration methods
This section outlines the configuration methods that need to be
performed for UNIX, Windows, and mixed SAN environments.
• Autoconfiguring the devices
This section outlines the device autoconfiguration specifics in a SAN
environment.
• Manually configuring the robotics