Dot Hill Systems II 200 FC - Manual (Page 61)

Chapter 4 Connecting Your Array 4-13
Figure 4-8 SANnet II 200 SATA Array Attached to Two Hosts and Two Expansion Units
4.6 Setting 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.”
Cable to drive
RAID array
Cable to host
Expansion unit 1
Expansion unit 2
Loop A (left-side drive ports)
Loop B (right-side drive ports)
H/D/RCC
H/D/RCC