Bitmap selection for remote copying of updates

摘要

In one embodiment of the present description, a copy relationship is established between a storage location at a first site and a storage location at a second site in a data storage system, wherein a dynamically assignable bitmap preset to one of a plurality of different predetermined bit patterns is selected as a function of both the availability of the selected bitmap and the type of predetermined bit pattern identified for the selected bitmap. The selected bitmap may be assigned as an out-of-sync bitmap wherein updates to the storage location at one site, which are to be copied to the storage location at the other site, are indicated in the selected bitmap, and data writes being written to the storage location at the one site, are copied to the storage location at the other site, using the selected bitmap as an out-of-sync bitmap. Other aspects are described.

主权项

1. A method, comprising:
establishing a copy relationship between a storage location at a first site and a storage location at a second site in a data storage system, wherein said establishing includes: selecting a dynamically assignable bitmap preset to one of a plurality of different predetermined bit patterns from a plurality of dynamically assignable bitmaps preset to a plurality of different predetermined bit patterns, as a function of both the availability of the selected bitmap and the type of predetermined bit pattern identified for the selected bitmap; assigning the selected bitmap as an out-of-sync bitmap wherein updates to the storage location at the second site, which are to be copied to the storage location at the first site, are indicated in the selected bitmap; and copying data writes being written to the storage location at one site, to the storage location at the other site, using the selected bitmap as an out-of-sync bitmap.