HP MSA 2040 SAN Storage - Manual (Page 23)

Connecting controller and drive enclosures 23
Figure 12 Cabling connections between MSA 2040 controllers and SFF drive enclosures
The figure above provides sample diagrams reflecting cabling of MSA 2040 controller enclosures and
D2700 6 Gb drive enclosures.
The diagram at left shows fault-tolerant cabling of a dual-controller enclosure and D2700 6 Gb drive
enclosures featuring dual-expansion modules. Controller module 1A is connected to expansion module
2A, with a chain of connections cascading down (blue). Controller module 1B is connected to the lower
expansion module (5B), of the last drive enclosure, with connections moving in the opposite direction
(green). Fault-tolerant cabling allows any drive enclosure to fail—or be removed—while maintaining
access to other enclosures.
The diagram at right shows the same storage components connected using straight-through cabling. Using
this method, if a drive enclosures fails, the enclosures that follow the failed enclosure in the chain are no
longer accessible until the failed enclosure is repaired or replaced.
P1
Controller A
Controller B
1A
1B
P2 P1
P1
P1
P1
P1
P2 P1
P2 P1
2A
2B
3A
3B
4A
4B
5A
5B
P2
P2
P2
P2
P2
P1
Controller A
Controller B
P2
P1
P1
P2
P1
P2
P1 P2
P1 P2
1A
1B
2A
2B
3A
3B
4A
4B
5A
5B
Fault-tolerant cabling Straight-through cabling
P1
P2
P1
P2
P2