Installation guide

Logical Hardware Configuration
HP-UX version 11.00.03 Administering Fault Tolerant Hardware 5-17
The following guidelines apply to logical SCSI bus definitions:
■ Logical SCSI buses must be named lsm0 to lsm15.
■ Physical hardware paths must be occupied by a SCSI adapter card (for
example, U501). The second physical hardware path is the standby device.
■ The adapter card that is used for standby in one logical SCSI bus cannot be
used as the primary card in another logical SCSI bus.
■ The specification of the location of the root disk (rt=1) can only be specified
for logical SCSI buses that connect to disks containing the root file system. (At
run time, the system automatically attaches the root (rt=1) and boot (bt=1)
variables to the appropriate lsm definition line in the /stand/conf file.)
■ On systems with StorageWorks disk enclosures, the proper SCSI ID is 15 for a
primary controller and 14 for a standby controller; however, for
single-initiated external ports connected to NARROW SCSI devices, use 7 for
the SCSI ID (because NARROW SCSI devices cannot communicate with the
controller if the port SCSI ID number is 8 or greater). On systems with
Eurologic disk enclosures, the proper SCSI ID is 7 for a primary controller and
6 for a standby controller.
■ Termination should not be enabled (tm0=0, tm1=0) on dual-initiated buses.
Termination should be enabled (tm0=1) for single-initiated buses. Note that
tape and CD-ROM devices are connected to single-initiated buses (as external
devices).
■ The value for termination power (tp) should always be 1.
The lsm number and the instance number are directly related. The system assigns
instance numbers when the system boots. They reflect the order in which
ioconfig binds that class of hardware device to its driver (which is determined
by the lsm definitions in the CONF file). The instance numbers of the logical SCSI
buses are fixed and do not change (without rebooting). The digit at the end of the
lsm# string and the third component of the logical hardware path (for example,
14/0/0) are always the same and both specify the actual instance number.
Table 5-3 lists the corresponding logical, physical, and instance addresses for the
logical SCSI bus definitions for Figure 5-6.
Table 5-3. Logical SCSI Bus Hardware Path Definition
Logical SCSI
Bus
Hardware
Path
Instance
Number
Active SCSI
Port
Standby SCSI
Port
lsm0 14/0/0 0 0/2/7/1 0/3/7/1
lsm1 14/0/1 1 0/2/7/2 0/3/7/2
lsm2 14/0/2 2 0/2/7/0 none