Loop ID

Each onboard port or port on an expansion module corresponds to a fixed loop ID, as shown in orange and blue marks in Figure 7-2.

• SAS disk enclosures can be cascaded to onboard interface modules or 12 Gbit/s SAS expansion modules in slots IOM 1.
• High-density disk enclosures are deployed in dual-uplink networking and require two expansion ports for cascading. The loop ID is the smaller one between two loop IDs to which the two cascading ports correspond.

  For example, the loop ID is 3 if ports P0 and P1 (marked by 3 and 4 in Figure 7-2) in slots IOM 1 are used to cascade a high-density disk enclosure.

Figure 7-2 12 Gbit/s SAS expansion modules in slots IOM 1

Disk Enclosure ID

DAEXXX indicates a disk enclosure ID. The first X indicates the controller enclosure ID, the second X indicates the hexadecimal loop ID, and the third X indicates the number of disk enclosures connected in a loop.

• For loops 1 to 6, the second X is 1, 2, ..., 5, and 6, and the third X ranges from 0 to 7 (0 for the first disk enclosure, 1 for the second disk enclosure, and so on).
• For example, the ID of the first disk enclosure in loop 2 of controller enclosure 0 is DAE020.

Table 7-6 describes the rules for naming disk enclosure IDs in each loop.