Patent ID: 6772303
Filing Date: 2004-08-03
Classification: G06F

Abstract:
A method of resynchronizing data contained in a data storage system having primary and backup storage sites both coupled to a data mover, the primary storage site coupled to a host that provides write data to the primary storage site, the data mover serving to mirror data stored at the primary storage site upon the backup storage site, where during predetermined error conditions the data mover stores data received by the storage system in the primary storage site without mirroring the data to the backup storage site, the method comprising:after termination of an error condition, the data mover performing a static resynchronization process comprising: identifying data received during the error condition at the primary storage site without mirroring to the backup storage site; reading the identified data from the primary storage site at one or more read times; writing the read data to the backup storage site; and the primary storage site receiving update data from the host for storage while no error condition is occurring, the update data representing changes to data already existing on the primary storage site, and in response: the data mover determining whether the static resynchronization process is in progress, and if not, copying the update data to the backup storage site; if the static resynchronization process is in progress, the data mover determining whether the static resynchronization process is already processing data corresponding to the existing data, and if not, copying the update data to the backup storage site; if the static resynchronization process is already processing data corresponding to the existing data, the data mover copying the update data to the backup storage site only if the host provided the update data to the primary storage site after the static resynchronization read time for the data already being processed.