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US 6,192,027 B1Granted
Apparatus, system, and method for dual-active fibre channel loop resiliency during controller failure
AssigneeInternational Business Machines Corporation
InventorMohamad El-Batal
Life of this patent
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Abstract
This invention relates generally to Fibre Channel Loop topology in a computer system and more particularly to structure and method for by-passing a failed controller connected in a dual-active mode Fibre Channel Loop.
Claims17
A device bypass circuit for a fibre channel communications loop, said circuit comprising:
- a first clock recovery circuit coupled to a first input port for receiving a first device signal from a first device and for generating a first regenerated device signal;
- a second clock recovery circuit coupled to a second input port for receiving a first controller signal from a first controller and for generating a first regenerated controller signal;
- a signal detection unit for detecting a valid first device signal and for generating a selector signal having a first state when a valid first device signal is detected and a second state when no valid first device signal is detected;
- and
- a switchable selector circuit receiving said first regenerated device signal, said first regenerated controller signal, and said first selector signal;
- said switchable selector circuit selectively passing one of said first regenerated device signal or said first regenerated controller signal in response to said first or second state of said first selector signal.
3 more elements
A Fibre Channel communication system comprising:
- at least one controlled device;
- a first dual-active controller operable to control said at least one controlled device;
- a second dual-active controller operable to control said at least one controlled device;
- a first loop resiliency circuit coupled between said first controller and said controlled device;
- a second loop resiliency circuit coupled between said second controller and said controlled device;
- and
- a fibre channel communications loop extending between said controlled device and said loop resiliency circuit for providing Fibre Channel protocol compliant communications among and between said controlled device and said first and second controllers.
4 more elements
In a Fibre Channel Loop connected information storage and retrieval system, a method for bypassing a non-responsive input/output or disk array controller to maintain Fibre Channel Loop coherency, said method comprising the steps of:
- receiving, by a first device controller, a first input signal from a first controlled device over said Fibre Channel loop;
- reconditioning said first input signal to reduce noise and jitter;
- monitoring, by a signal detection circuit, the clock pulse timing characteristics of a first controller output signal from said first device controller derived from said first input signal to a second device controller;
- and
- selectively redirecting said reconditioned first input signal as the output signal of said first controller when said monitored signal fails to meet predetermined signal characteristics.
2 more elements
Dependencies are inferred from the claim text.