Data Protector General Guidelines - HP 12000 Design Manual

necessary to administer the backup and restore activities directly from the Cell Manager itself,
because any client within the cell (as supported) can connect to the Cell Manager over the
network and be used to administrate the activities of the cell.
Disk Agent: install the Disk Agent on client systems you want to back up. The Disk Agent reads
or writes data from a disk on the system and sends or receives data from the Media Agent.
The Disk Agent is also installed on the Cell Manager, allowing you to back up data on the
Cell Manager, the Data Protector configuration, and the IDB.
Media Agent: (For servers that have direct access to tape drives.) During a backup session,
the Media Agent receives data from the Disk Agent and sends it to the tape device (which
can be directly attached or allocated over a SAN). During a restore session, the Media Agent
locates data on the backup medium and sends it to the Disk Agent. The Disk Agent then writes
the data to the disk. The Media Agent also manages the robotics control of a library. If a
system has both the client agent and the media agent installed then it can perform LAN-free
backups.

Data Protector General Guidelines

The following Data Protector guidelines apply to a VLS regardless of whether deduplication is
enabled or disabled:
Tape block size: set the tape block size to 256 KB in the Drive Properties of the virtual tape
drives configured in Data Protector.
Multiple paths to tape devices: in an environment with shared tape devices, there may be
"MultiPath" devices within Data Protector (where there are both direct and indirect paths to
the same shared tape drive). To ensure optimal performance, verify that the direct path is used
for backups.
Data Protector media pool policy: the recommended media pool policy is "Loose" and
"Appendable." This prevents dedicating specific cartridges to specific backup jobs which
results in inefficient media usage and can also cause significant impact to VLS deduplication
because it does not consistently fill tapes.
Disable multiplexing: set the concurrency to 1 (default is set in the Drive Properties, and can
also be set in the backup specifications), because multiplexing is not recommended for virtual
libraries due to the performance impact on restores and on deduplication. Because you can
create additional drives easily in the virtual library and allocate them to Media Agents as
necessary, sufficient backup streams can be concurrently written without requiring multiplexing.
Disable client backup compression.
Disable inventory rescans on jobs. They cause a read element to every slot in the library and
can disrupt backups.
Limit the virtual library to a maximum of 20,000 slots.
136 VLS Configuration and Backup Application Guidelines