Compaq StorageWorks HSG60 ACS Solution Software V8.6 for Sun Solaris Installation and Configuration Guide

6–4 HSG60 ACS Solution Software Version 8.6 for Sun Solaris Installation and Configuration Guide
When speaking of a single controller, it is correct to say Active-Passive as that describes
the state of the channels as shown inTable 6–3.
When both controllers are active in a controller pair, the correct designation is
Active-Active.
Hubs
Hubs create the connections within a loop. They also contain port-bypass circuitry to
allow malfunctioning nodes to be bypassed, thus allowing the loop to continue to function.
NOTE: We do not support cascading hubs. The largest supported loop configuration using hubs
consists of 12 ports maximum.
Switches
Switches enable multiple connections to each other. With switches, Fibre Channel is
removed from some of the limitations of arbitrated loop, such as throughput, single point
of failure, and sizing of configuration.
As indicated earlier, the complexity of a configuration can increase in direct proportion to
the number of components added in the Fibre Channel storage network. While switches
provide a great deal of flexibility and scalability of storage access and sharing, they also
tend make transparent the path from server to storage.
IMPORTANT: Take the time to plan your configuration, test the portions of it and record the
various connections and paths.
.
Table 6–2 Case 2: Active-Active (Describes the controller pair)
Channel 1 - Active Channel 2 - Passive Controller A Primary Ch 1,
Standby Ch 2
Channel 1 - Passive Channel 2 - Active Controller B Primary Ch 1,
Standby Ch 2
Table 6–3 Example of Active-Passive with a Single Controller
Channel 1 - Active Channel 2 - Passive Controller A Primary Ch 1,
Standby Ch 2