System and method for fibrechannel fail-over through port spoofing

A method for appliance back-up comprising:

• sending a status message from a primary appliance to a standby appliance indicating that the primary appliance is operational;
• if the standby appliance does not receive the status message or the status message is invalid:
• writing a shutdown message to a storage device;
• reading the shutdown message stored in the storage device;
• disabling the primary appliance from processing requests or commands;
• causing a standby appliance address to be identical to a primary appliance address;
• and
• causing the standby appliance to process the requests or commands.

A method for appliance back-up comprising:

• monitoring a primary appliance for an indication of a failure, the primary appliance having a primary appliance address,
• wherein if the failure occurs:
• writing a message to a storage device;
• in response to the message, disabling the primary appliance from processing requests or commands;
• causing a standby appliance address of a standby appliance to be identical to the primary appliance address;
• and
• processing the requests or commands.

A communications system, comprising:

• at least one storage device;
• a first appliance configured to receive requests or commands for communicating with one or more of the at least one storage devices via a first communications link, the first appliance having a first appliance address;
• and
• a second appliance configured to:
• transmit, at selected times, messages to the first appliance via a second communications link different from the first communications link;
• wherein:
• the first appliance is further configured to:
• communicate with one or more of the at least one storage devices in response to a received request or command;
• and
• in response to each message received from the second appliance, provide an indication to the second appliance of a status of the first appliance via the second communications link;
• and
• the second appliance is further configured to:
• monitor the status of the first appliance based, at least in part, on the indications received from the first appliance;
• determine whether a proper indication is received in response to each message;
• assume an emulation address comprising the first appliance address in order to receive the requests or commands addressed to the first appliance, based, at least in part, on a failure to receive a proper indication;
• process the requests or commands addressed to the first appliance, after assuming the emulation address;
• continue to monitor the status of the first appliance, after assuming the emulation address;
• if failure to receive a proper indication from the first appliance is due to a problem relating to the first appliance, determine that the problem has been resolved;
• and
• transmit to the first appliance via the second communications link information directing the first appliance to resume receiving requests and commands directed to the first appliance address, when the second appliance determines that the problem has been resolved;
• and
• the first appliance is further configured to resume receiving requests and commands directed to the first appliance address, in response to the information.

A communications system, comprising:

• a network;
• at least one storage device;
• a first appliance coupled to the network via a first communications link, to receive requests or commands for communicating with one or more of the at least one storage device, the first appliance having a first appliance address;
• and
• a second appliance coupled to the network;
• wherein the first appliance is configured to:
• communicate with one or more of the at least one storage devices, based, at least in part, on the requests or commands;
• and
• provide an indication to the second appliance indicating a status of the first appliance;
• and
• the second appliance is configured to:
• determine a status of the first appliance, based, at least in part, on the indication;
• assume an emulation address comprising the first appliance address to receive the requests or commands directed to the first appliance, based at least in part, on the indication;
• process the requests or commands addressed to the first appliance after assuming the emulation address;
• cause the first appliance to disconnect itself from the network based at least in part, on the second status;
• determine a second status of the first appliance after the first appliance is disconnected from the network;
• and
• instruct the first appliance via a second communications link different from the first communications link, to connect itself to the network based, at least in part, on the second status.

A system comprising

• a first device configured to process requests or commands received from a network, via a first communications link, the first device having a first address;
• and
• a second device configured to:
• determine a status of the first device;
• assume an emulation address including, at least in part, the first address, based, at least in part, on the determination;
• cause the first device to disconnect itself from the network based, at least in part, on the determination;
• determine a second status of the first device after the first device disconnects from the network;
• and
• instruct the first device via a second communications link different from the first communications link, to connect itself to the network based, at least in part, on the second status.

A method of operating a communications system comprising a first appliance to process requests or commands received from a network via a first communications link and a second appliance, the method comprising:

• determining by a second appliance a status of a first appliance;
• assuming by the second appliance an address associated with the first appliance, based, at least in part, on the status;
• processing requests or commands addressed to the first appliance, by the second appliance, after assuming the address;
• causing the first appliance to disconnect itself from the network based, at least in part, on the determination, by the second appliance;
• determining by the second appliance a second status of the appliance after the first appliance is disconnected from the network;
• and
• instructing the first appliance via a second communications link different from the first communications link, to begin a start-up procedure to resume reception and processing of requests or commands based, at least in part, on the second status, by the second appliance.

A communications system, comprising:

• at least one storage device;
• a first appliance to receive requests or commands for communicating with one or more of the at least one storage devices, the first appliance having a first appliance address;
• and
• a second appliance;
• wherein the first appliance is configured to:
• communicate with one or more of the at least one storage devices in response to a received request or command;
• and
• provide an indication to the second appliance of a status of the first appliance;
• and
• the second appliance is configured to:
• determine a status of the first appliance based, at least in part, on the indication;
• assume an emulation address comprising the first appliance address in order to receive the requests or commands addressed to the first appliance, based, at least in part, on the indication;
• process the requests or commands addressed to the first appliance, after assuming the emulation address;
• and
• write a message to one of the at least one storage devices to cause the first appliance to disable itself, based at least in part, on the indication.

A communications system, comprising:

• a network;
• at least one storage device;
• a first appliance coupled to the network, to receive requests or commands for communicating with one or more of the at least one storage devices, the first appliance having a first appliance address;
• a second appliance coupled to the network;
• and
• a communications link between the first appliance and the second appliance
• wherein the first appliance is configured to:
• communicate with one or more of the at least one storage devices, based, at least in part, on the requests or commands;
• and
• provide an indication to the second appliance indicating a status of the first appliance;
• and
• the second appliance is configured to:
• determine a status of the first appliance, based, at least in part, on the indication;
• assume an emulation address comprising the first appliance address to receive the requests or commands directed to the first appliance, based at least in part, on the indication;
• process the requests or commands addressed to the first appliance after assuming the emulation address;
• and
• writing a message to the storage device to cause the first appliance to disable itself from processing requests or commands, if the link is broken.

A communications system, comprising:

• at least one storage device;
• a first appliance having a first appliance address, the first appliance being configured to:
• receive requests or commands for communicating with one or more of the at least one storage devices via a first communications link;
• and
• a second appliance configured to:
• transmit, at selected times, messages to the first appliance via a second communications link different from the first communications link;
• and
• wherein:
• the first appliance is further configured to:
• communicate with one or more of the at least one storage devices in response to a received request or command;
• in response to each message received from the second appliance, provide an indication to the second appliance of a status of the first appliance via the second communications link;
• and
• inform the second appliance, via the second communications link, of a problem relating to an operation of the first appliance, if the first appliance detects a problem relating to the operation of the first appliance;
• and
• the second appliance is further configured to:
• assume an emulation address comprising the first appliance address in order to receive the requests or commands addressed to the first appliance, if informed of a problem relating to the operation of the first appliance;
• process the requests or commands addressed to the first appliance, after assuming the emulation address;
• and
• instruct the first appliance via the second communications link to begin a start-up procedure, if informed that the problem has been repaired.