Exchanging locations of an out of synchronization indicator and a change recording indicator via pointers

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. Locations of the first data structure and the second data structure are exchanged, subsequent to the consistency group being formed successfully.

主权项

1. A method, comprising:
storing in an out of synchronization bitmap indications of storage locations that need to be copied for forming a consistency group, wherein an out of synchronization bitmap pointer stored in a non-volatile metadata track controlled by a primary computational device points to the out of synchronization bitmap; storing in a change recording bitmap indications of new host writes, subsequent to starting a point in time copy operation to form the consistency group, wherein a change recording bitmap pointer stored in the non-volatile metadata track points to the change recording bitmap, wherein the out of sychronization bitmap is stored is a first location of a bitmap metadata track and the change recording bitmap is stored in a second location of the bitmap metadata track, wherein the first location and the second location have intervening locations that separate the first location and the second locations in the bitmap metadata track, wherein the bitmap metadata track is controlled by a primary computational device from which an asynchronous remote copy is performed to a remote computational device, and wherein the point in time copy operation to form the consistency group is performed in the remote computational device; and exchanging locations within the bitmap metadata track of the out of synchronization bitmap with the change recording bitmap by pointing the change recording bitmap pointer stored in the non-volatile metadata track to the first location that stores the out of synchronization bitmap from second location that stores the change recording bitmap, and by pointing the out of synchronization bitmap pointer stored in the non-volatile metadata track to the second location that stores the change recording bitmap from the first location that stores the out of synchronization bitmap, subsequent to the consistency group being formed successfully, wherein no merging of contents of the out of synchronization bitmap with the change recording bitmap is performed.