Installation guide

Logical Hardware Configuration
HP-UX version 11.00.03 Administering Fault Tolerant Hardware 5-13
Logical SCSI Manager Configuration
The logical SCSI manager has two primary purposes: to serve as a generalized host
bus adapter driver front-end and to implement the concept of a logical SCSI bus.
A logical SCSI bus is one that is mapped independently from the actual hardware
addresses. A physical SCSI bus can have one or two initiators located anywhere in
the system, but the logical SCSI manager allows you to target each SCSI bus by its
logical SCSI address without regard to its physical location or whether it is single-
or dual-initiated. By using a logical SCSI manager, you can configure (and
reconfigure) dual-initiated SCSI buses across any SCSI controllers in the system.
The LSM also provides transparent failover between partnered physical
controllers (which are connected in a dual-initiated mode).
The logical SCSI manager subsystem addressing convention is as follows:
■ The first-level address, 14, is the logical SCSI manager nexus (LSM).
■ The second-level address is a constant, 0, which represents a transparent slot.
■ The third-level address is the logical SCSI bus number (described in
ftsmaint output as the LSM Adapter). The logical SCSI bus number
represents a defined logical SCSI bus and can be 0–15.
■ The fourth-level address is the SCSI bus address associated with the device
(the SCSI target ID). The number can be 0–15, but the following rules apply:
– for a system with a Eurologic Voyager LX500 Ultra II enclosure: 6 and 7
are reserved (for the controllers) and 15 is reserved (for the SCSI Enclosure
Services (SES) module)
– for a system with a StorageWorks enclosure: 14 and 15 are reserved (for
the controllers)
(There is no associated description on the fourth-level address line in
ftsmaint output.)
■ The fifth-level address is the logical unit number (LUN) of the device, which
is usually 0. (The device description appears on the fifth-level address line in
ftsmaint output.)
Figure 5-6 illustrates a sample logical SCSI manager configuration. Each device
represents a logical “node” in the system.