Patent ID: 6484187
Filing Date: 2002-11-19
Classification: G06F,Y10S

Abstract:
A method for coordinating operations among multiple remote copy backup sessions of a data storage system, where each session includes a primary storage subsystem and a corresponding backup storage subsystem, where the data storage system includes a master data set with individual areas corresponding to each session and a common area corresponding to all sessions, the method comprising the operations of:a first one of the sessions receiving a command request from a host, including a command and a start time; in response to the command request, the first session performing operations comprising: disallowing changes to the master data set; storing the command in the common area; retrieving time stamps from the sessions, each time stamp representing a past time to which data in that session can be recovered; determining a most recent one of the returned time stamps, and if the command's start time is after the most recent returned time stamp, listing the command and the most recent time stamp in the common area of the master data set; if the command's start time is before the most recent returned time stamp, listing a cancel instruction in the common area of the master data set; re-allowing changes to the master data set.