HP A6828A and A6829A PCI Dual Channel Ultra160 SCSI Host Bus Adapters Installation Guide

Installing the A6828A or A6829A Adapter
Installing the Adapter
Chapter 2 9
During an adapter replacement operation, SAM performs a Critical
Resource Analysis (CRA), which checks all channels on the target
adapter for critical resources that will be temporarily unavailable while
the adapter is shut down.
Planning and Preparation
As mentioned earlier, for the most part, SAM prevents you from
performing OLAR procedures that would adversly affect other areas of
the HP-UX system. See Configuring HP-UX For Peripherals for detailed
information.
Critical Resources
Replacing an adapter that is still operating can have adverse
consequences. As power to the slot must be off when the old adapter is
removed and the new adapter is inserted, you must consider the effects
of shutting down the adapter’s functions.
This is particularly important if no online failover or backup adapter to
pick up those functions is installed. For example:
• Which mass storage devices will be temporarily disconnected when
the adapter is shut down?
• Will a critical networking connection be lost?
A critical resource causes a system crash or prevents the operation from
completing successfully if the resources were temporarily suspended or
disconnected. For example, if the SCSI adapter to be replaced connects to
the unmirrored root disk or swap space, the system will crash when the
adapter is shut down.
During an OLAR procedure, it is essential to check the targeted adapter
for critical resources. In addition, it is necessary to check the effects of
existing disk mirrors and other situations where an adapter’s functions
can be taken over by another adapter that will not be affected.
As mentioned earlier, SAM performs a thorough CRA automatically and
presents options based on its findings. If you determine that critical
resources will be affected by the procedure, you can replace the adapter
when the system is offline. On the other hand, if you are required to take
an action immediately, you can use the rad command to try an online
addition of a backup adapter and deletion of the target adapter.