Methods and structure for implementing logical device consistency in a clustered storage system

A method operable on a plurality of storage controllers within a clustered storage system, each of the storage controllers communicatively coupling host systems with storage devices, wherein the method comprises:

• generating, by a storage controller, a proposed Logical Unit Number (LUN) for a logical volume provisioned at the storage devices;
• communicating, by the storage controller, with each of other storage controllers within the clustered storage system requesting that the other storage controllers determine if the proposed LUN is in use;
• determining, by the storage controller, if the proposed LUN is in use by the other storage controllers;
• responsive to determining that that the proposed LUN is not in use by the other storage controllers:
• assigning, by the storage controller, the proposed LUN to the logical volume;
• and
• responsive to determining that the proposed LUN is in use by at least one of the other storage controllers;
• generating, by the storage controller, a new proposed LUN;
• re-trying communication with each of the other storage controllers requesting that the other storage controllers determine if the new proposed LUN is in use;
• and
• assigning the new proposed LUN to the logical volume responsive to determining that the new proposed LUN is not in use by the other storage controllers.

A storage controller within a clustered storage system communicatively coupling a host system with storage devices, the storage controller comprising:

• an interface operable to communicate with other storage controllers within the clustered storage system;
• and
• a control unit operable to receive a proposed Logical Unit Number (LUN) for a logical volume provisioned by another storage controller within the clustered storage system, and to determine if the proposed LUN is in use by the storage controller,
• the control unit further operable to:
• transmit a message to the other storage controller indicating that the proposed LUN is not in use responsive to determining that the proposed LUN is not in use by the storage controller;
• and
• transmit a message to the other storage controller indicating that the proposed LUN is in use responsive to determining that the proposed LUN is in use by the storage controller.