Method of verifying data consistency between local and remote mirrored data storage systems

A method of verifying data consistency between active and mirroring data processing systems, each of which includes data storage resources having storage media upon which user data is stored, comprising the steps of:

• storing the user data in the data storage resources of each of the active and mirroring systems;
• calculating the metadata which describes the user data stored at each of the active and mirroring systems when the user data is stored;
• storing the calculated metadata in association with the user data;
• creating time stamp information which describes the time at which the user data was first stored on the active system;
• storing the time stamp information in association with the user data stored in the data storage resources of both the active and mirroring systems;
• sending the time stamp information and the metadata obtained from the data storage resources of the active system to the mirroring system;
• reading the time stamp information and the metadata from the data storage resources of the mirroring system;
• comparing the metadata sent from the active system with the time stamp information and metadata read from the mirroring system;
• and
• upon detecting a discrepancy in the metadata from the active and mirroring systems, replacing the user data in the one of the active or mirroring systems having the less current temporal time stamp information with the user data from the one of the active or mirroring systems having the more current temporal time stamp information.