CONSISTENT POINT-IN-TIME COPY OF A CONSISTENT ASYNCHRONOUS MIRROR TARGET WITHOUT PAUSING A CONSISTENT ASYNCHRONOUS MIRROR COPY

摘要

Provided are techniques for delayed consistent point-in-time copy from a secondary device in an asynchronous mirror relationship. A consistent asynchronous mirror copy that includes an asynchronous mirror copy from a primary volume to a secondary volume and a point-in-time copy from the secondary volume to a tertiary volume is performed. A point-in-time copy is created from the secondary volume to an accessible consistent copy volume. In response to receiving a request to access a track of the accessible consistent copy volume, it is determined whether to access the track of one of the secondary volume, the tertiary volume, and the accessible consistent copy volume. A response to the request is provided with data accessed from the determined one of the secondary volume, the tertiary volume, and the accessible consistent copy volume.