Patent ID: 8417849

Claim:
A method to adjust a multi-path device reservation, comprising: supplying a computing device and a storage controller interconnected with physical communication path; supplying a multi-path reserve/recovery apparatus external to both said computing device and said storage controller, and in communication with said input output channel, and comprising an establish module, a resign module, a disband module, and a remove other port module; configuring by said multi-path reserve/recovery apparatus said physical communication path to comprise a first plurality of logical communication path; configuring by said multi-path reserve/recovery apparatus a first communication path group to include a second plurality of the logical communication paths, wherein the first plurality of logical communication paths is greater than the second plurality of logical communication paths; reserving by said multi-path reserve/recovery apparatus, for a period of time to perform a sequence of operations, a data storage device in communication with said storage controller, wherein said data storage device reservation is held by said first communication path group; detecting by said multi-path reserve/recovery apparatus a failed communication path configured in said first communication path group; configuring a second communication path group by removing said failed communication path from said first communication path group, wherein said second communication path group maintains said data storage device reservation, issuing by said multi-path reserve/recovery apparatus a remove port command, wherein: said issuing step comprises generating by said multi-path reserve/recovery apparatus a remove port command reciting an interface_id specifying said first control unit port, and issuing said remove port command to said storage controller using any of said plurality of control unit ports except said first control unit port, said storage controller comprises a plurality of control unit ports; said first plurality of communication paths interconnect with said storage controller using said plurality of control unit ports; said failed communication path interconnects with said storage controller using a first control unit port, wherein said first control unit port is one of said plurality of control unit ports, generating by said multi-path reserve/recovery apparatus a two byte interface_id that is data storage device independent, and that uniquely identifies a control unit port that is to be remove from the communication path group by the remove port command; verifying a communication path group id; removing communication paths to said reserved data storage device that utilize the first control unit port; determining by said multi-path reserve/recovery apparatus if any of said first communication paths utilize said first control unit port; operative if none of said first communication paths utilize said first control unit port: taking no action; maintaining said device reservation with said first communication path group.