Optimizing performance

Various factors can affect autoloader performance, particularly in a network environment or if the drive is not on a dedicated SCSI bus.

If your autoloader is not performing as well as expected, consider the following points before contacting HP Support at www.hp.com/support.

•Is the autoloader connected to a suitably-rated built-in SCSI bus or HBA, see “Why is the SCSI bus type important?” on page 3. Suitably-rated means an Ultra Wide or higher SCSI specification, such as an Ultra 160 SCSI Host Bus Adapter.

•Is the autoloader on a dedicated SCSI bus? For optimum performance, we recommend that the autoloader is the only device on the SCSI bus. If it is not, ensure other devices are the same SCSI specification as your autoloader model. If they are single-ended, the bus will switch to single-ended mode with a lower transfer speed.

•Do not put autoloaders and hard disks on the same SCSI bus.

•Is the SCSI bus terminated correctly. The last device on the SCSI bus must be terminated.

•Have you installed the correct device drivers for your operating system and backup application? See “Backup software and drivers” on page 5.

•Are you backing up across a network? The network load may be affecting the speed of transfer or your backup application may only be appropriate for a single-server environment.

•Is the backup application writing buffers at the correct speed? You may need to tune the transfer, buffer and block size settings to optimize the speed that the application writes data to the autoloader. HP StorageWorks DAT autoloaders have an internal buffer of 8 MB.

38