HP MSA 1040 SAN Storage - Manual (Page 22)

22 Installing the enclosures
Figure 10 Cabling connections between MSA 1040 controllers and LFF drive enclosures
The diagram at left (above) shows fault-tolerant cabling of a dual-controller enclosure cabled to MSA 2040
6 Gb 3.5" 12-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 (4B) 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 (above) shows the same storage components connected using straight-through
cabling. Using this method, if a drive enclosure fails, the enclosures that follow the failed enclosure in the
chain are no longer accessible until the failed enclosure is repaired or replaced.
Both illustrations in Figure 10 show the maximum number of supported enclosures that can be cabled
together in an MSA 1040 system configuration: up to four enclosures (including the controller enclosure).
Controller A
Controller B
1A
1B
In
Out
2A
2B
3A
3B
4A
4B
In Out
In Out
In Out
In Out
In Out
Fault-tolerant cabling
Controller A
Controller B
In
Out
In Out
In Out
In Out
In Out
In Out
Straight-through cabling
1A
1B
2A
2B
3A
3B
4A
4B