Patent ID: 8676750
Filing Date: 2014-03-18
Classification: G06F

Abstract:
1. A method for synchronizing data stored on primary and secondary storage volumes in a distributed data recovery system, the method comprising: associating N data recovery relationships between a primary volume and N secondary volumes by way of implementing N data structures respectively, wherein the N data structures are bitmaps, monitoring a plurality of indicators for a respective track in each one of the N data structures, wherein each data structure comprises a first indicator that indicates whether data stored on a first track of the primary volume has been updated, due to a first operation performed by a host application, and wherein one or more of the N data structures are stored in at least a first data storage medium with high speed data access rates; implementing a primary data structure comprising a second indicator for monitoring and indicating that data stored on the first track of the primary volume has been updated, in response to detecting that the first indicator in at least one of the N data structures is set to a first value, wherein the primary data structure is a bitmap, resetting the plurality of indicators in the primary data structure when resetting the plurality of indicators in the secondary data structure, wherein during a state of reset: staging and destaging a single primary bitmap rather than storing and reading N secondary bitmaps for reducing a response time to a host; entering a suspended state for marking write operations in the primary bitmap on the primary data structure upon a break in communication between the primary volume and one of the N secondary volumes, wherein corresponding data which has been set in the primary bitmap on the primary data structure is copied to the secondary bitmap on each of the secondary data structure; and providing an acknowledgment to the host that at least one of the N data structures reflects the updated status of the data stored in the first track of the primary volume, so that the host continues to perform a second operation without waiting for synchronization between the primary volume and the respective secondary volume to be completed.