Method and apparatus for supporting legacy mode fail-over driver with iSCSI network entity including multiple redundant controllers

摘要

The invention is directed to a method and apparatus for supporting legacy mode fail-over drivers with an iSCSI network entity including multiple redundant controllers. In an exemplary aspect of the present invention, to support legacy mode fail-over drivers with an iSCSI network entity including multiple redundant controllers, the following configuration constraints may be placed on the iSCSI network entity and its iSCSI configuration: (1) the network device need have two or more redundant controllers; (2) the portals on each controller may or may not be formed into portal groups; (3) the portal groups may not span controllers (i.e., the target portal groups are limited in scope to a single controller); (4) the same iSCSI target name need be exported by all redundant controllers (i.e., the targets span all controllers of the iSCSI network entity, making the LUNs available to all controllers); (5) the target portal group numbers on the redundant controllers need have unique target portal group tags (i.e., all target portal group tags are unique across all portal groups in the iSCSI network entity. However, the target portal group tags do not need to be unique for different iSCSI targets); and (6) all targets are available from at least one target portal group on each controller. In addition, the initiator may use a single ISID for all sessions, use a different ISID for a different session, or the like. The present configuration constraints may enable the normal behavior of the legacy mode SCSI driver to locate and use redundant SCSI paths to the SCSI devices on the iSCSI target.