Retrieving diagnostics information in an N-way clustered raid subsystem

A method comprising the steps of:

• generating, at a storage controller, an exception event and associated exception data;
• indicating the exception event in a status page of the storage controller, wherein the status page is a section of memory in the storage controller that is accessible by multiple storage servers including a storage server accessing the status page, wherein the storage server is a network storage server that provides storage access services to network storage clients via a network;
• registering the storage server with the storage controller by writing a unique token from the storage server to the status page of the storage controller when there is no token from another storage server written in the status page, wherein one storage server can read the exception data from the storage controller at a time;
• and
• only when the storage server is registered with the storage controller, reading the exception data by the storage server from the storage controller.

A network storage server that provides storage access services to network storage clients via a network, the network storage server comprising:

• an exception detection device configured to detect an exception event generated by a storage controller and indicated by a status page of the storage controller, wherein the status page is a section of memory in the storage controller that is accessible by multiple network storage servers including the network storage server;
• a registration request device in communication with said exception detection device, said registration request device configured to register the network storage server with the storage controller by requesting the storage controller to write a unique token into the status page of the storage controller;
• and
• a data read device in communication with said registration request device, said data read device configured to read exception data associated with the exception event from the storage controller only if the network storage server is registered with the storage controller.

A system for reading exception data comprising a network storage server and a storage controller wherein:

• the network storage server provides storage access services to network storage clients and includes:
• an exception detection device configured to detect an exception event;
• a registration request device in communication with said exception detection device, said registration request device configured to register the network storage server with the storage controller;
• and
• a data read device in communication with said registration request device, said data read device configured to read the exception data from the storage controller only if the network storage server is registered with the storage controller;
• and
• the storage controller includes:
• a memory including a status page, wherein the status page is accessible by multiple network storage servers including the network storage server;
• an exception generation device configured to generate the exception event and the exception data and indicate the exception event in the status page;
• a registration device in communication with said registration request device, said registration device configured to register the network storage server with the storage controller by writing a unique token from the network storage server into the status page;
• and
• a data storage in communication with said data read device, said data storage containing the exception data.

A storage controller in a network storage system, the storage controller comprising:

• a processor;
• an exception generation device configured to generate exception data and indicate the exception event in a status page of the storage controller in response to an exception event in the network storage system, wherein the status page is a section of memory in the storage controller that is accessible by multiple network storage servers;
• a communication interface configured to, when executed by the processor, receive a registration request including a unique token from a network storage server that provides storage access services to network storage clients;
• and
• a registration device configured to, when executed by the processor:
• deny registration of the network storage server if another network storage server is already registered with the storage controller, which is indicated by a token from the other network storage server written in the status page;
• and
• allow registration of the network storage server with the storage controller by writing the token from the network storage server into the status page if no other network storage server is already registered with the storage controller;
• wherein the communication interface is further configured to transmit the exception data to the network storage server after the network storage server is registered with the storage controller.