Dot Hill Systems 4524 - Reverse-Cabling between a Dual-Controller 4 U Enclosure and Three 4 U Drive Enclosures; Straight-Through Cabling between a Dual-Controller 4 U Enclosure and Three 4 U Drive Enclosures

AssuredSAN 4004 Series Setup Guide 47
4004 Series 4U controller enclosures cabled to supported drive enclosures
Figure 42 Reverse-cabling between a dual-controller 4U enclosure and three 4U drive enclosures
Figure 42 shows reverse-cabling of a 4004 Series dual-controller 4U enclosure and J6G56 drive
enclosures configured with dual-expansion modules. Controller module 0A is connected to expansion
module 1A, with a chain of connections cascading down (blue). Controller module 0B is connected to the
lower expansion module (3B), of the last expansion enclosure, with connections moving in the opposite
direction (green). Reverse cabling allows any expansion enclosure to fail—or be removed—while
maintaining access to other enclosures.
Figure 43 Straight-through cabling between a dual-controller 4U enclosure and three 4U drive enclosures
Figure 43 shows the same storage components used in Figure 42, but they are connected using
straight-through cabling. Using this method, if an expansion enclosure fails, the enclosures that follow the
failed enclosure in the chain are no longer accessible until the failed enclosure is repaired or replaced.
Refer to these diagrams when cabling multiple compatible drive enclosures together with the 4004 Series
controller enclosure. The cabling diagrams reflect maximum configuration.
TIP: Per common convention in cabling diagrams, the controller enclosure is shown atop the stack of
connected enclosures. In reality, for
Figure 44–Figure 49, you can invert the order of the stack for optimal
weight and placement stability within the rack. The schematic representation of the cabling remains
unchanged. See the rackmount bracket kit installation instructions for your product(s) for more detail.
Controller
enclosure
0
Drive
enclosure
In
Out
Out
0B
0A
1A
1B
Controller A
Controller B
1
In
In
Out
Out
2A
2B
In
In
Out
Out
3A
3B
In
Drive
enclosure
2
Drive
enclosure
3
Controller
enclosure
0
Drive
enclosure
In
Out
Out
0B
0A
1A
1B
Controller A
Controller B
1
In
In
Out
2A
2B
In
In
Out
3A
3B
In
Drive
enclosure
2
Drive
enclosure
3
Out
Out