SAS cabling considerations

Cabling your system correctly is one of the most important aspects of planning for a dual storage I/O adapter (IOA) configuration. For RAID configurations that have disk expansion drawers, correct cabling is required to provide redundancy between each adapter and the disk expansion drawer.

Follow these guidelines when you cable your system.

• For RAID configurations on a 5887 EXP 24S SFF generation-2-bay drawer, X or Y cables are used depending on the type of adapter and mode setting of the disk expansion drawer. This criteria is to provide redundancy for the SAS ports between each controller and disk expansion drawer and redundancy for the SAS ports for each disk drive.
• For RAID configurations on a 5886 EXP 12S disk expansion drawer, X cables provide redundancy for two wide SAS ports between each controller and disk expansion drawer, and it also provides redundancy for two narrow SAS ports for each disk drive.
• For RAID configurations with a 5802 or 5803 PCIe 12X I/O drawer, AT cables are used. SAS topology is incorporated with in the IO drawer wiring. This wiring provides redundancy similar to X cables.
• For RAID configurations with internal SAS disk slots, YR cables provide redundancy for two narrow SAS ports between each controller and internal disk enclosure, and it also provides redundancy for two narrow SAS ports for each disk drive.

To see examples of how to cable dual storage IOA configurations, see Serial attached SCSI cable planning.