I/O Drawer Ras - IBM p5 590 System Handbook

On each planar board, the ten PCI-X slots have a 3.3V PCI bus signaling and
operates at 33 MHz, 66 MHz, or 133 MHz, depending on the adapter. All PCI-X
slots are PCI 2.2 compliant and are hot-plug enabled (see 2.7.6, "Logical view of
a RIO-2 drawer" on page 44).
PCI adapters have different bandwidth requirements, and there are functional
limitations on the number of adapters of a given type in an I/O drawer or a
system.
The complete set of limitations are described in the Hardware Information
Center. This is regularly updated and should be considered as the reference for
any questions related to PCI limitations.
In a RIO-2 I/O-drawer all the I/O slots can be populated with high speed adapters
(for example, Gigabit Ethernet, Fibre Channel, ATM or Ultra320 SCSI adapters).
All can be populated, but in some situations we might not get optimum
performance on each by bandwidth limitation.

2.7.7 I/O drawer RAS

If there is an RIO-2 failure in a port or cable, an I/O planar board can route data
through the other I/O connection and share the remaining RIO-2 cable for I/O.
For power and cooling, each drawer has two redundant DC power supplies and
four high reliability fans. The power supplies and fans have redundancy built into
them, and the drawer can operate with a failed power supply or a failed fan. The
hard drives and the power supplies are hot-swappable, and the PCI adapters are
hot-plug.
All power, thermal, control, and communication systems are redundant in order
to eliminate outages due to single-component failures.
I/O subsystem communication and monitoring
There are two main communication subsystems between the CEC and the I/O
drawers. The power and RAS infrastructure are responsible for gathering
environmental information and controlling power on I/O drawers. The RIO-2
loops are responsible for data transfer to and from I/O devices.
Power and RAS infrastructure
The power cables that connect each I/O drawer and the bulk power assembly
(BPA) provide both electricity power distribution and reliability, availability, and
serviceability infrastructure functions that include:
Powering all system components up or down, when requested. These
components include I/O drawers and the CEC.
IBM Eserver p5 590 and 595 System Handbook
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