Minihub Canister - Silicon Graphics TP9400 RAID Owner's Manual

2: The Controller Enclosure

Minihub Canister

22
Because the two power supplies provide redundancy, you can hot swap a failed power
supply, replacing it while the controller enclosure is in operation.
Note: An abrupt power loss to the controller enclosure can cause data corruption,
especially if the power loss occurred when data was being downloaded to cache memory
or written to disk. If a sudden power loss causes data corruption, you may need to use
the storage management software (TPSSM7) to recover the data.
If a power supply fails, the green Power Supply indicator on the power supply will be
off and the amber Power Supply Fault indicator on the controller fan canister on the front
of the controller enclosure will glow. If both power supplies fail, the fault indicator
cannot come on. For more information about indicators, see "Checking the Controller
Enclosure Indicator Lights" on page 36.
If you replace the power supply canister and continue to experience problems, the
controller enclosure may have defective components or connections. Check the storage
management software (TPSSM7) for indications of other component failures.
A minihub canister is an interface card located at the rear of the controller enclosure
(Figure 2-13). It is a single, removable unit that provides the Fiber Channel interface
between a controller enclosure and hosts and drives. The rear of the controller enclosure
can accommodate up to eight interface cards that function as minihubs: up to four host
canisters and up to four drive minihub canisters. Each minihub has two Fibre Channel
connections. You connect the host-interface or drive-interface cables to the respective
minihub.
There are two types of minihubs: GBIC and SFP.
• A GBIC (Gigabit Interface Converter) minihub has two Fibre Channel connectors
called GBIC modules. GBIC minihubs are used with 1 GB interface controllers.
• An SFP (Small Form-factor Pluggable) minihub has two Fibre Channel connectors
called SFP transceivers. SFP minihubs are used with 2 GB interface controllers.
The minihubs are interchangeable and can be installed on either the host-side or the
drive-side. However, you cannot mix different types of minihubs within a controller
enclosure.
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