System, method, and computer program product for on-line replacement of a host bus adapter

• Main Authors: McGowen, Michael E, Edwards, William C, Brown, Peter J, Belusar, Craig M
• Format: Patent
• Language: English
• Published: 17.08.2004

1. Field of the Invention A system and method for enabling multi-path functionality between a host bus adapter (HBA) in a host computer of a storage system and at least one storage device is disclosed. The host computer includes a processor and associated memory, and an operating system including a PnP manager that maintains a logical device stack for the storage device. An HBA-specific filter driver intercepts responses from the underlying HBA driver to specified PnP requests. These responses are modified to prevent standard Microsoft operating system SCSI class device drivers from being loaded for devices attached to the HBA. Instead, the modified responses cause a multi-path SCSI class device driver to be loaded. The filter driver also monitors the status of the paths to a device and, upon request, provides status information to the multi-path SCSI class device driver. The multi-path SCSI class driver may use this status information to decide whether to make a particular path a primary path. The actions required to make a path a primary path may be performed by the filter driver, e.g., through a function call to the filter driver initiated by the multi-path SCSI driver.