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 system, comprising:
a memory; and a processor coupled to the memory, wherein the processor performs operations, the operations comprising: storing in a plurality of first data structures that indicate storage locations that need to be copied for forming a consistency group, and storing in a plurality of second data structures 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; processing each track of the metadata storage area by performing:
selecting a metadata track to be processed;securing read access to the selected metadata track, and subsequent to securing the read access to the selected metadata track determining 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 no new host writes, the updating of the first data structure with the contents of the second structure is not performed, the read access to the selected metadata track is released, and determining whether any further tracks in the metadata storage area are left to be processed; andin response to determining that the second data structure indicates that there are new host writes, performing:
changing access of the metadata track to secure write access to the metadata track;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;updating the second data structure to indicate that the second data structure is in an initialized state; andreleasing the write access to the metadata storage area and determining whether any further metadata storage area is left to be processed; and in response to processing all of the plurality of metadata tracks maintained in the metadata storage area, setting an indicator indicating that all of the plurality of second data structures are now initialized, wherein the setting of the indicator is performed by a non-background task, wherein the updating of the first data structure with the contents of the second data structure comprises performing an OR operation of corresponding bits of the first data structure and the second data structure.