Chapter 2. Architecture and technical overview
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attached to EXP24S SFF Gen2 Drawers. The EXP24S can be either attached to SAS
adapters on the system nodes or on the PCIe Expansion Drawer.
For a list of adapters and their supported slots, please see 2.7, “PCI adapters” on page 70.
I
Figure 2-19 I/O connectivity options available for Power E870 and Power E880
For more information on PCIe Expansion Drawers, please see 2.9.1, “PCIe Gen3 I/O
expansion drawer” on page 77.
2.5.2 Service Processor Bus
The redundant service processor bus connectors are located on the rear of the control unit
and the system nodes. All the service processor (SP) communication between the control unit
and the system nodes flows though these cables.
Unlike the previous generations where a given pair of enclosures would host the service
processors, on Power E870 and Power E880 as a standard, redundant service processor
cards are installed on the control unit as well as redundant clock cards.
The cables used to provide communications between the control units and system nodes
depend on the amount of system nodes installed. When a system node is added, a new set of
cables is also added.
Disk support: There is no support for disks directly installed on the system nodes and
PCIe Expansion Drawers. If directly attached SAS disk are required, they need to be
installed in a SAS disk drawer and connected to a supported SAS controller in one of the
PCIe slots.
PCIe Gen3 x16
PCIe Adapter for
Expansion Drawer
PCIe Gen3 x16
PCIe Gen3 x16
PCIe Gen3 x16
PCIe Gen3 x16
PCIe Gen3 x16
SAS Adapter
System Node
EXP24S SFF Gen2 Drawer
PCIe Expansion Drawer
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EXP24S SFF Gen2 Drawer
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