ANTICIPATORY APPLICATION OF MEASURES FOR DETECTING AND PREVENTING OR MEASURE FOR AMELIORATING FOR POTENTIAL LOGICAL UNIT THRASHING IN MULTIPLE REQUESTORS

摘要

PROBLEM TO BE SOLVED: To prevent potential LUN thrashing in a multiple requestor storage system having an active-passive pair of resource controllers.;SOLUTION: An arbitrator component detects what kind of access each of the two I/O requestors has for the active-passive pair of resource controllers. In detecting that each of the two requesters has usable access to both of the active-passive pair of resource controllers, one of the active-passive pair of resource controllers is selected. In detecting that one of the two requestors has usable access to only one of the active-passive pair of controllers, only one of the active-passive pair of controllers is selected. In detecting that each of the two requesters has usable access to different one of the active-passive pair of controllers, I/O of one of the active-passive pair of controllers is disabled or I/O is enabled but participation of one of the requestors for deciding to select a controller as an active controller is disabled.;COPYRIGHT: (C)2004,JPO&NCIPI