Patent ID: 6708175
Filing Date: 2004-03-16
Classification: G06F,H04L,Y10S

Abstract:
A method for controlling access to files in a storage area network which includes a plurality of interconnected data processing nodes when said nodes have been divided into a plurality of distinct partitions as a result of a node failure or network communication failure, said method comprising the steps of:determining for each partition, P1, . . . , Pn, the number of nodes, N1, . . . , Nn, respectively, that constitute a quorum for that partition, and the times, T1, . . . , Tn, at which said node failure is reported to each of said node sets, also respectively; granting access to said file to at least one of said nodes for a limited time duration, D, said access grant coming from a node set in which a quorum of nodes concurs with said granting; accessing said file from said at least one node during times that said permission duration has not expired; and prohibiting access of said file from said failed node until a time at least equal to max(T1, . . . , Tn)+D.