Figure 54 Indirect Library Access
Note that you cannot use a shared library if the client system that controls the robotics, castor, in our example, fails.
Direct Library Access
When the SAN concept is used, Data Protector can be configured with a SCSI Library so that each client system has its own access to library robotics and drives. This is called Direct Library Access
There is no single “controlling client system” for the robotics: a failure of the system controlling the robotics does not exclude any other system from using the library. This is performed without reconfiguration. Several client systems can be used to control the robotics.
Figure 55 on page 180 shows an HP StorageWorks DLT multidrive library attached via a SAN to two client systems. Both client systems have access to the library and to both drives. The SCSI protocol is used for communication with the library.
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