Volume initialization for asynchronous mirroring

A storage facility, comprising:

• a local volume having local regions;
• a remote volume having remote regions in a one-to-one correspondence with the local regions;
• and
• a local processor configured to convey first data from the local regions to the corresponding remote regions, to receive, while conveying the first data, a request to update a given local region, and to mark the given local region, to create, subsequent to conveying the first data, a local snapshot referencing the local regions and to convey, subsequent to creating the local snapshot, second data from the marked local region to the remote storage system.

A computer program product, the computer program product comprising:

• a non-transitory computer readable storage medium having computer readable program code embodied therewith, the computer readable program code comprising:
• computer readable program code configured to convey first data from local regions of a local volume of a local storage system to a remote storage system having a remote volume with remote regions in a one-to-one correspondence with the local regions;
• computer readable program code configured to receive, while conveying the first data, a request to update a given local region, and to mark the given local region;
• computer readable program code configured to create, subsequent to conveying the first data, a local snapshot referencing the local regions;
• and
• computer readable program code configured to convey, subsequent to creating the local snapshot, second data from the marked local region to the remote storage system.