Dot Hill Systems II 200 FC service manual Setting Loop IDs on Expansion Units

RAID array

Expansion unit 1

Loop A (left-side drive ports)

Expansion unit 2

H/D/RCC

H/D/RCC

Cable to drive Loop B (right-side drive ports)

Cable to host

Figure 4-8SANnet II 200 SATA Array Attached to Two Hosts and Two Expansion Units

4.6Setting Loop IDs on Expansion Units

When an expansion unit is attached to a RAID array, unique, hard-assigned loop IDs are assigned to each expansion unit drive. A loop ID is the decimal version of an arbitrated loop physical address (AL_PA). The lowest number loop ID is the lowest priority address on the loop.

On the left front side of an expansion unit, an ID switch is used to set the loop IDs for the disk drives to a different range of values so that the same IDs are not repeated by RAID units and expansion units on the same loop.

Setting the loop ID on an array or expansion unit requires dropping the front bezel out of the way and removing the small vertical plastic cap on the left side of the bezel that covers the left rackmount tab. Rackmount tabs are also referred to as “ears.”

Chapter 4 Connecting Your Array 4-13