5.4 Four-Rack Cabling for X8M Racks

This section provides the cabling tables to connect four X8M racks together, all of which use RoCE Network Fabric.

Note:

The following conventions were used in the cabling notation for connecting multiple racks together.

• The spine switch (also referred to as SS) is in U1 for all racks.

• The leaf switches are referred to as Lower Leaf (LL) and Upper Leaf (UL).

• The leaf switches are located as follows:

  • At rack unit 20 (U20) and 22 (U22) in Oracle Exadata X8M-2 or Storage Expansion Rack X8M-2

  • At rack unit 21 (U21) and rack unit 23 (U23) in Oracle Exadata X8M-8

• The cable lengths shown in the following lists assume that the racks are adjacent to each other, the cables are routed through a raised floor, and there are no obstacles in the routing between the racks. If the racks are not adjacent, or use overhead cabling trays, then they may require longer cable lengths. Cable lengths up to 100 meters are supported.

• Only optical cables (with additional transceivers) are supported for lengths greater than 5 meters.

• For X8M-8 systems with three database servers and 11 storage servers only, you must adjust the following multi-rack cabling information. On such systems only, port 30 on the leaf switches is connected to a database server and is not used as an inter-switch link. Consequently, in the following tables, any connection to port number 30 on any leaf switch must instead connect to port number 34 on the same leaf switch. For example, R1-UL-P30 must change to R1-UL-P34, R1-LL-P30 must change to R1-LL-P34, and so on. These changes only apply to X8M-8 systems with three database servers and 11 storage servers.

The following illustration shows the cable connections for the four spine switches (Rack1-spine, Rack2-spine, Rack3-spine, and Rack4-spine) when cabling two racks together:

Description of the illustration x8m-multi-rack-4-cabling-guide.eps

The following table describes the cable connections for the first spine switch (R1-SS) when cabling four racks together:

Table 5-6 Leaf Switch Connections for the First Rack in a Four-Rack System

Leaf Switch	Connection	Cable Length
R1 UL within Rack 1	R1-UL-P5 to R1-SS-P5 R1-UL-P7 to R1-SS-P7	3 meters
R1 UL to Rack 2	R1-UL-P31 to R2-SS-P5 R1-UL-P33 to R2-SS-P7	5 meters
R1 UL to Rack 3	R1-UL-P6 to R3-SS-P5 R1-UL-P32 to R3-SS-P7	5 meters
R1 UL to Rack 4	R1-UL-P4 to R4-SS-P5 R1-UL-P30 to R4-SS-P7	10 meters
R1 LL within Rack 1	R1-LL-P5 to R1-SS-P13 R1-LL-P7 to R1-SS-P15	3 meters
R1 LL to Rack 2	R1-LL-P31 to R2-SS-P13 R1-LL-P33 to R2-SS-P15	5 meters
R1 LL to Rack 3	R1-LL-P4 to R3-SS-P13 R1-LL-P6 to R3-SS-P15	5 meters
R1 LL to Rack 4	R1-LL-P30 to R4-SS-P13 R1-LL-P32 to R4-SS-P15	10 meters

The following table describes the cable connections for the second spine switch (R2-SS) when cabling four full racks together:

Table 5-7 Leaf Switch Connections for the Second Rack in a Four-Rack System

Leaf Switch	Connection	Cable Length
R2 UL to Rack 1	R2-UL-P5 to R1-SS-P6 R2-UL-P7 to R1-SS-P8	5 meters
R2 UL within Rack 2	R2-UL-P31 to R2-SS-P6 R2-UL-P33 to R2-SS-P8	3 meters
R2 UL to Rack 3	R2-UL-P6 to R3-SS-P6 R2-UL-P30 to R3-SS-P8	5 meters
R2 UL to Rack 4	R2-UL-P4 to R4-SS-P6 R2-UL-P32 to R4-SS-P8	5 meters
R2 LL to Rack 1	R2-LL-P5 to R1-SS-P14 R2-LL-P7 to R1-SS-P16	5 meters
R2 LL within Rack 2	R2-LL-P31 to R2-SS-P14 R2-LL-P33 to R2-SS-P16	3 meters
R2 LL to Rack 3	R2-LL-P6 to R3-SS-P14 R2-LL-P32 to R3-SS-P16	5 meters
R2 LL to Rack 4	R2-LL-P4 to R4-SS-P14 R2-LL-P30 to R4-SS-P16	5 meters

The following table describes the cable connections for the third spine switch (R3-SS) when cabling four full racks together:

Table 5-8 Leaf Switch Connections for the Third Rack in a Four-Rack System

Leaf Switch	Connection	Cable Length
R3 UL to Rack 1	R3-UL-P5 to R1-SS-P11 R3-UL-P7 to R1-SS-P12	5 meters
R3 UL to Rack 2	R3-UL-P6 to R2-SS-P11 R3-UL-P31 to R2-SS-P12	5 meters
R3 UL within Rack 3	R3-UL-P30 to R3-SS-P11 R3-UL-P32 to R3-SS-P12	3 meters
R3 UL to Rack 4	R3-UL-P4 to R4-SS-P11 R3-UL-P33 to R4-SS-P12	5 meters
R3 LL to Rack 1	R3-LL-P7 to R1-SS-P19 R3-LL-P4 to R1-SS-P20	5 meters
R3 LL to Rack 2	R3-LL-P6 to R2-SS-P19 R3-LL-P31 to R2-SS-P20	5 meters
R3 LL within Rack 3	R3-LL-P30 to R3-SS-P19 R3-LL-P32 to R3-SS-P20	3 meters
R3 LL to Rack 4	R3-LL-P5 to R4-SS-P19 R3-LL-P33 to R4-SS-P20	5 meters

The following table describes the cable connections for the fourth spine switch (R4-SS) when cabling four full racks together:

Table 5-9 Leaf Switch Connections for the Fourth Rack in a Four-Rack System

Leaf Switch	Connection	Cable Length
R4 UL to Rack 1	R4-UL-P5 to R1-SS-P9 R4-UL-P7 to R1-SS-P10	10 meters
R4 UL to Rack 2	R4-UL-P4 to R2-SS-P9 R4-UL-P6 to R2-SS-P10	5 meters
R4 UL to Rack 3	R4-UL-P31 to R3-SS-P9 R4-UL-P33 to R3-SS-P10	5 meters
R4 UL within Rack 4	R4-UL-P30 to R4-SS-P9 R4-UL-P32 to R4-SS-P10	3 meters
R4 LL to Rack 1	R4-LL-P5 to R1-SS-P17 R4-LL-P7 to R1-SS-P18	10 meters
R4 LL to Rack 2	R4-LL-P4 to R2-SS-P17 R4-LL-P6 to R2-SS-P18	5 meters
R4 LL to Rack 3	R4-LL-P31 to R3-SS-P17 R4-LL-P33 to R3-SS-P18	5 meters
R4 LL within Rack 4	R4-LL-P30 to R4-SS-P17 R4-LL-P32 to R4-SS-P18	3 meters