Configuring HP-UX For Peripherals

38 Chapter2
Managing PCI Cards with OLAR
PCI Card OLAR Overview and Concepts
potentially conflict with the current driver. If a new card is not
acceptable, SAM or rad will report that the card cannot be resumed.
• During the replacement process, the driver instance for each port on
the target card runs in a suspended state. I/O to the ports are either
queued or failed while the drivers are suspended. When the
replacement card is brought on-line, the driver instances resume
normal operation. Each driver instance must be capable of resuming
and controlling the corresponding port on the replacement card.
The PCI specification allows a single physical card to contain more than
one port. For example, a single-port SCSI bus adapter can not be
replaced by a dual-port adapter, even if the additional port on the card
was identical to the original SCSI bus adapter. Attempting to replace a
card with another card that has more ports than the original could result
in the additional port(s) being claimed by other drivers if an ioscan
occurs while the slot power is on. Recovering from that condition would
require a system reboot.
Critical Resources
Replacing a card that is still operating can have extensive ramifications.
Since power to the slot must be off when the old card is removed and the
new card is inserted, the effects of shutting down the card’s functions
must be considered.
This is particularly important if there is no on-line fail-over or backup
card to pick up those functions. For example:
• Which mass storage devices will be temporarily disconnected when
the card is shut down?
• Will a critical networking connection be lost?
A critical resource is one that would cause a system crash or prevent the
operation from successfully completing if the resource were temporarily
suspended or disconnected. For example, if the SCSI adapter to be
replaced connects to the un-mirrored root disk or swap space, the system
will crash when the card is shut down.
During an OLAR procedure, it is essential to check the targeted card for
critical resources, as well as the effects of existing disk mirrors and other
situations where a card’s functions can be taken over by another card
that will not be affected.
Fortunately SAM performs a thorough critical resource analysis