Scsi Addresses; Planning The Sas Configuration; About Sas; Sas Cables And Connectors - HP StorageWorks 1/8 User's And Service Manual

SCSI addresses

Verify that each device on the bus has a unique SCSI address (SCSI ID). The pre-configured SCSI
address for the Autoloader is 4. If 4 is already used for another device, you will need to change the
SCSI address of the Autoloader during the installation process.
NOTE:
The HBA also has a SCSI address, which is typically 7.
NOTE:
Use the HP Library & Tape Tools to check your server's parallel SCSI configuration. The HP Library
& Tape Tools utility is available without cost at http://www.hp.com/support/TapeTools.

Planning the SAS configuration

The key steps in planning the SAS configuration are obtaining a suitable HBA and cable.
The Autoloader uses two SCSI logical unit numbers (LUNs) and requires an HBA with multiple LUN
support. Most HP SAS RAID controllers support Tape Libraries; many non-HP SAS RAID controllers to
not support Tape Libraries. To verify the specifications of your HBA or find a list of compatible HBAs,
review the compatibility matrix on the Enterprise Backup Solutions web site at: http://www.hp.com/
go/ebs.
CAUTION:
Do not connect the Autoloader to a SAS RAID controller unless the EBS matrix shows that the controller
is qualified with the Autoloader. The server might not be able to boot when the Autoloader is connected
to a non-supported SAS RAID controller.

About SAS

Serial Attached SCSI (SAS) is a computer bus technology mainly used to transfer data to and from
storage devices, including disk drives and tape drives. SAS-1 (LTO-4) is designed to transfer data at
3 Gb/sec, which is comparable to the speed attained by Ultra320 SCSI. SAS-2 (LTO-5) is designed
to transfer data at 6 Gb/sec.

SAS cables and connectors

SAS uses serial connections, with a direct connection between the host server and each of the storage
devices. This eliminates the need to configure SCSI busses and assign SCSI IDs, as is required for
parallel SCSI devices.
Most SAS HBA ports have four SAS channels. A tape drive uses one channel, so each HBA port can
support up to four tape drives. You can use a cable with one connector on each end, but only one
channel will be used. To use the other channels, you can purchase a SAS fanout cable with a connector
for each tape drive, as shown in Figure 7 on page 30.
HP StorageWorks 1/8 G2 Tape Autoloader User and service guide 29