MERGING AN OUT OF SYNCHRONIZATION INDICATOR AND A CHANGE RECORDING INDICATOR IN RESPONSE TO A FAILURE IN CONSISTENCY GROUP FORMATION

摘要

A first data structure stores indications of storage locations that need to be copied for forming a consistency group. A second data structure stores indications of new host writes subsequent to starting a point in time copy operation to form the consistency group. Read access is secured to a metadata storage area and a determination is made as to whether the second data structure indicates that there are any new host writes. In response to determining that the second data structure indicates that there are new host writes, write access is secured to the metadata storage area, the first data structure is updated with contents of the second data structure to determine which additional storage locations need to be copied for formation of a next consistency group, and the second data structure is updated to indicate that that the second data structure is in an initialized state.

主权项

1. A method, comprising:
storing in a plurality of first data structures indications that indicate storage locations that need to be copied for forming a consistency group, and storing in a plurality of second data structures indications that indicate new host writes subsequent to starting a point in time copy operation to form the consistency group, wherein a first data structure and a second data structure are maintained in a track, and a plurality of tracks are maintained in a metadata storage area; in response to determining that the second data structure indicates that there are new host writes, updating the first data structure with contents of the second data structure to determine which additional storage locations need to be copied for formation of a next consistency group by performing an OR operation of corresponding bits of the first data structure and the second data structure, and updating the second data structure to indicate that the second data structure is in an initialized state; in response to determining that the second data structure indicates that there are no new host writes, updating of the first data structure with the contents of the second data structure is not performed; and in response to processing all of the plurality of tracks maintained in the metadata storage area, setting an indicator by a non-background task to indicate that all of the plurality of second data structures are now in the initialized state.