Cable requirements
SAS uses serial connections, with a direct connection between the host server and each of the storage
devices. This method eliminates the need to configure SCSI buses 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. The SAS fanout cable recommended for use with the library can connect up to four SAS tape drives to
a single SAS HBA port.
Figure 10: Example SAS fanout cable
Connectors
The host end of the cable must have the same type of connector as the HBA external SAS port.
The tape drive has a mini-SAS connector. The connector is keyed in location 4, which is the standard location
for end devices. If you use a cable other than the one recommended for use with the product, verify that it is
keyed in location 4.
CAUTION:
Mini SAS connectors are keyed. Do not force a SAS cable mini-SAS connector into the tape drive mini-
SAS port because it might be keyed differently.
World Wide identifiers
A unique identifier called a World Wide Name (WWN) or World Wide Identifier (WWID) identifies a SAS tape
drive. The library assigns the World Wide identifier to the drive bay. When a tape drive is replaced, the World
Wide identifier is reassigned to the new tape drive.
The operating system tracks the World Wide identifier for the drive on each HBA channel. Each of the drive
connectors on a fanout cable is associated with an HBA channel. Once a drive has been connected, keep it
on the same channel to retain the association between the HBA channel and World Wide identifier.
Parallel SCSI configuration information
The parallel SCSI libraries use the Ultra 320 SCSI LVD interface. The libraries use a separate SCSI ID for
each tape drive, with dual LUNs on the master drive SCSI ID to control the tape drive (LUN 0) and library
robotic (LUN 1). Hewlett Packard Enterprise recommends that each Ultrium tape drive has its own bus when
possible.
The parallel SCSI libraries incorporate a wide SCSI-2 or SCSI-3 low-voltage differential (LVD) SCSI bus.
Make sure that your SCSI host adapter or controller supports these standards.
Parallel SCSI configuration information
29
