Interface Card OL* Support Guide

Chapter 1

PCI Card OL* Overview and Concepts

Planning and Preparation

For the most part, these tools prevent you from performing OL* procedures that would adversely affect other

areas of the server. This section provides you with important information that can help minimize errors or

problems when performing OL* procedures.

Card Compatibility

Online Addition

When adding an interface card online, the ﬁrst issue that must be resolved is whether the new card is

compatible with the system. Each OL* capable PCI slot provides a set amount of power. The card to be added

cannot require more power than is available. Some systems may have only one slot per bus with sufﬁcient

power.

The card must also operate at the slot’s bus frequency. See “Frequency Mismatch” on page 21.

When a card is added to the system, the appropriate driver for that card must be conﬁgured in the kernel

before beginning the operation. In most cases, the added card should be the same type as a card already in the

system, and the driver will be in the kernel. Kernel Conﬁguration is accessible through kcweb. If the required

driver is not present, a reboot will be required to load the driver. The card could be added while the system is

down, or added online after rebooting. A reboot may not be needed if the OS version supports Dynamic

Loadable Kernel Modules (DLKM).

• If the necessary driver is not present you can load it manually.

• If the driver is static and not conﬁgured in the kernel, then the card cannot be Online Added. The card

could be physically inserted online, but no driver would claim it.

Online Replacement

When replacing an interface card online, the replacement card must be identical. This is referred to as

like-for-like replacement and should be adhered to because using a similar card, but not identical, may cause

unpredictable results. For example, a newer version of the target card which is identical in terms of hardware

may contain an updated ﬁrmware version that could potentially conﬂict with the current driver. If a new card

is not acceptable, pdweb will report that the card cannot be resumed, the Attention Button method will result

in the slot not being powered up, and olrad will return an error.

• 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 online, 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. 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. The ports would be claimed properly,

and 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.