IBM eX5 Implementation Guide

Chapter 3. IBM System x3850 X5 and x3950 X5 71

򐂰 Two x3850 X5 servers connected to form a single image 8-socket server. This

configuration is sometimes referred to as a

2-node server.

3.6.1 Memory scalability with MAX5

The MAX5 memory expansion unit permits the x3850 X5 to scale to an additional 32 DDR3

DIMM sockets.

Connecting the single-node x3850 X5 with the MAX5 memory expansion unit uses four QPI

cables, part number 59Y6267, as listed in Table 3-7. Figure 3-13 shows the connectivity.

Figure 3-13 Connecting the MAX5 to a single-node x3850 X5

Connecting the MAX5 to a single-node x3850 X5 requires one IBM MAX5 to x3850 X5 Cable

Kit, which consists of four QPI cables. See Table 3-7.

Table 3-7 Ordering information for the IBM MAX5 to x3850 X5 Cable Kit

3.6.2 Two-node scalability

The 2-node configuration also uses native Intel QPI scaling to create an 8-socket

configuration. The two servers are physically connected to each other with a set of external

QPI cables. The cables are connected to the server through the QPI bays, which are shown in

Figure 3-7 on page 66. Figure 3-14 on page 72 shows the cable routing.

MAX5: The configuration of two nodes with MAX5 is not supported.

Tip: As shown in Figure 3-12 on page 70, you maximize performance when you have four

processors installed because you have four active QPI links to the MAX5. However,

configurations of two and three processors are still supported.

Rack rear

Part number Feature code Description

59Y6267 4192 IBM MAX5 to x3850 X5 Cable Kit (quantity 4 cables)

72 IBM eX5 Implementation Guide

Figure 3-14 Cabling diagram for two node x3850 X5

Connecting the two x3850 X5 servers to form a 2-node system requires one IBM x3850 X5

and x3950 X5 QPI Scalability Kit, which consists of four QPI cables. See Table 3-8.

Table 3-8 Ordering information for the IBM x3850 X5 and x3950 X5 QPI Scalability Kit

No QPI ports are visible on the rear of the server. The QPI scalability cables have long rigid

connectors, allowing them to be inserted into the QPI bay until they connect to the QPI ports,

which are located a few inches inside on the planar. Completing the QPI scaling of two x3850

X5 servers into a 2-node complex does not require any other option.

Figure 3-15 on page 73 shows the QPI links that are used to connect two x3850 X5 servers to

each other. Both nodes must have four processors each, and all processors must be identical.

Rack rear

Part number Feature code Description

46M0072 5103 IBM x3850 X5 and x3950 X5 QPI Scalability Kit (quantity 4 cables)

Intel E7520 and E7530: The Intel E7520 and E7530 processors cannot be used to scale

to an 8-way 2-node complex. They support a maximum of four processors. At the time of

this writing, the following models use those processors:

򐂰 7145-ARx

򐂰 7145-1Rx

򐂰 7145-2Rx

򐂰 7145-2Sx

Chapter 3. IBM System x3850 X5 and x3950 X5 73

Figure 3-15 QPI links for a 2-node x3850 X5

QPI-based scaling is managed primarily through the Unified Extensible Firmware Interface

(UEFI) firmware of the x3850 X5.

For the 2-node x3850 X5 scaled through the QPI ports, when those cables are connected, the

two nodes act as one system until the cables are physically disconnected.

Firmware levels: It is important to ensure that both of the x3850 X5 servers have the

identical UEFI, integrated management module (IMM), and Field-Programmable Gate

Array (FPGA) levels before scaling. If they are not at the same levels, unexpected issues

occur and the server might not boot. See 9.10, “Firmware update tools and methods” on

page 509 for ways to check and update the firmware.

Partitioning: The x3850 X5 currently does not support partitioning.

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QPI Links