System and method for a redundant communication channel via storage area network back-end

A storage area network comprising:

• a plurality of loosely-coupled storage controllers arranged in a redundant configuration to provide, a plurality of servers, access to virtualized storage wherein one of the storage controllers operates as a master controller and the other storage controller or controllers operate as slave controllers;
• and
• means for communicating among the storage controllers over an alternative communications channel wherein;
• the storage area network comprises a plurality of physical disk drives coupled a respective back-end of each of storage controllers, said physical disk drives configured to provide the virtualized storage;
• and
• the means for communicating further comprises a respective portion on each one of the physical disk drives, wherein one or more messages are stored in each of the respective portions, said one or more messages being exchanged between the master controller and any of the slave controllers.

A storage area network comprising:

• a plurality of loosely-coupled storage controllers arranged in a redundant configuration to provide, a plurality of servers, access to virtualized storage, wherein one of the storage controllers operates as a master controller and the other storage controller or controllers operate as slave controllers;
• and
• means for communicating among the storage controllers over an alternative communications channel wherein;
• the storage area network comprises a plurality of physical disk drives coupled to a respective back-end of each of the storage controllers, said physical disk drives configured to provide the virtualized storage;
• and
• the means for communicating further comprises a respective portion on at least one additional disk drive, said at least one additional disk drive being separate from the physical disk drives, wherein one or more messages are stored in each of the respective portions, said one or more messages being exchanged between the master controller and any of the slave controllers.

A storage area network comprising:

• a plurality of loosely-coupled storage controllers arranged in a redundant configuration to provide, to a plurality of servers, access to virtualized storage, wherein one of the storage controllers operates as a master controller and the other storage controller or controllers operate as slave controllers;
• and
• a communication channel coupled to each of the controllers for communicating among the controllers, the communications channel comprising a memory device accessible by all of the storage controllers, said memory device configured to store one or more messages between the master controller and the slave controllers wherein;
• the storage area network comprises a plurality of physical disk drives coupled to a respective back-end of each of the storage controllers, said physical disk drives configured to provide the virtualized storage;
• and
• wherein the memory device further comprises a respective portion on at least one of the physical disk drives, wherein the one or more messages are stored in each of the respective portions.

A storage area network comprising:

• a plurality of loosely-coupled storage controllers arranged in a redundant configuration to provide, to a plurality of servers, access to virtualized storage, wherein one of the storage controllers operates as a master controller and the other storage controller or controllers operate as slave controllers;
• and
• a communication channel coupled to each of the controllers for communicating among the controllers, the communications channel comprising a memory device accessible by all of the storage controllers, said memory device configured to store one or more messages between the master controller and the slave controllers wherein;
• the storage area network comprises a plurality of physical disk drives coupled to a respective back-end of each of the storage controllers, said physical disk drives configured to provide the virtualized storage;
• and
• wherein the memory device further comprises a respective portion on each one of the physical disk drives, wherein the one or more messages are stored in each of the respective portions.

A storage area network comprising:

• a plurality of loosely-coupled storage controllers arranged in a redundant configuration to provide, to a plurality of servers, access to virtualized storage, wherein one of the storage controllers operates as a master controller and the other storage controller or controllers operate as slave controllers;
• and
• a communication channel coupled to each of the controllers for communicating among the controllers, the communications channel comprising a memory device accessible by all of the storage controllers, said memory device configured to store one or more messages between the master controller and the slave controllers;
• wherein the memory device includes one or more semiconductor memories and the one or more messages are stored on each of the semiconductor memories.

A storage area network comprising:

• a plurality of loosely-coupled storage controllers arranged in a redundant configuration to provide, to a plurality of servers, access to virtualized storage, wherein one of the storage controllers operates as a master controller and the other storage controller or controllers operate as slave controllers;
• and
• a communication channel coupled to each of the controllers for communicating among the controllers, the communications channel comprising a memory device accessible by all of the storage controllers, said memory device configured to store one or more messages between the master controller and the slave controllers wherein;
• the storage area network comprises a plurality of physical disk drives coupled to a respective back-end of each of the storage controllers, said physical disk drives configured to provide the virtualized storage;
• and
• wherein the memory device comprises a respective portion on at least one additional disk drives, said at least one additional disk drive being separate from the physical disk drives, wherein the one or more messages are stored in each of the respective portions.

A storage area network comprising:

• a plurality of loosely-coupled storage controllers arranged in a redundant configuration to provide, to a plurality of servers, access to virtualized storage, wherein one of the storage controllers operates as a master controller and the other storage controller or controllers operate as slave controllers;
• and
• a communication channel coupled to each of the controllers for communicating among the controllers, the communications channel comprising a memory device accessible by all of the storage controllers, said memory device configured to store one or more messages between the master controller and the slave controllers;
• wherein the one or more stored messages include respective digital signatures to permit authentication of each respective message.

A storage area network comprising:

• a plurality of loosely-coupled storage controllers arranged in a redundant configuration to provide, to a plurality of servers, access to virtualized storage, wherein one of the storage controllers operates as a master controller and the other storage controller or controllers operate as slave controllers;
• and
• a communication channel coupled to each of the controllers for communicating among the controllers, the communications channel comprising a memory device accessible by all of the storage controllers, said memory device configured to store one or more messages between the master controller and the slave controllers wherein;
• a primary communication channel among the storage controllers;
• and
• wherein at least one of the storage controllers is configured to use the memory device as an alternative communications channel if the primary communication channel is unavailable.

A method, in a storage area network comprising plural loosely-coupled redundant controllers, for providing a back-end message channel, the method comprising the steps of:

• arranging the controllers to include a master controller and one or more slave controllers;
• allocating a respective storage portion on each of a plurality of physical disk drives which are coupled to a respective back-end of each controller;
• in response to a first slave controller having a first message to forward to the master controller, writing of said first message to each of the storage portions by the first slave controller;
• and
• in response to the master controller having a second message to forward to a second slave controller;
• writing of said second message to each of the storage portions by the master controller.