HP Data Protector Software Performance White Paper

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Hardware compression
Most modern backup devices provide built-in hardware compression that can be enabled by
selecting the appropriate device file or SCSI address in the device configuration procedure.
Hardware compression increases the speed at which a tape drive can receive data, because
less data is written to the tape.
Recommendations:
1. Do not use software and hardware compression at the same time because double
compression decreases performance without giving better compression results.
2. Keep the software compression option disabled when an Ultrium drive is configured with
Data Protector.
When configuring a device, you can select the SCSI address from the drop-down list. Data
Protector automatically determines whether the device can use hardware compression or not.
Figure 58 illustrates which devices are detected during the automatic configuration process for
an Ultrium 960 drive. In this example, the hardware compression is selected. The end of the
device’s SCSI address is extended with the “C” option: Tape0:0:6:0C.
Figure 58. HP StorageWorks Ultrium 960 automatic configuration – SCSI address for hardware compression
Figure 59 shows that with the correct SCSI address selection the Hardware Compression option
(bottom left) is grayed out.
Figure 59. HP StorageWorks Ultrium 960 configuration – hardware compression enabled