Patent ID: 6820099
Filing Date: 2004-11-16
Classification: G06F,Y10S

Abstract:
A method for updating data contained in a base volume contained in a computerized data storage system connected to a production server on which the undated data is formed prior to writing the updated data to the snapshot volume, the updating appearing instantaneous to a user of the data, the base volume initially containing original data and finally containing updated data, comprising the steps of:satisfying data access requests from the original data in the base volume; forming the updated data on the production server; transmitting a signal from the production server to the computerized data storage system instructing the computerized data storage system to perform the step of forming the snapshot volume; transmitting the undated data from the production server to the computerized data storage system for writing to the snapshot volume; forming a snapshot volume in a memory of a controller of the computerized data storage system of the original data in the base volume; writing the updated data received from the production server to the snapshot volume; after writing the updated data to the snapshot volume, transmitting a signal from the computerized data storage system to the production server indicating that the updating is complete; rolling back the updated data from the snapshot volume to the base volume; satisfying the data access requests from the updated data in the base volume and in the snapshot volume while rolling back the updated data from the snapshot volume to the base volume; and after rolling back the updated data from the snapshot volume to the base volume, deleting the snapshot volume.