Patent attributes
Maintaining a set of extents corresponding to a portion of an initial logical volume that is to be copied includes initializing a table having entries corresponding to different portions of the initial logical volume, where each of the entries is initialized with a first value, following initializing the table, providing a second value different from the first value to an entry in the table corresponding to a portion of the initial logical volume to which a write operation is performed and establishing the set of extents, where the first value is provided to entries in the table that correspond to portions of the initial logical device indicated by the extents. Data of the initial logical volume corresponding to the set of extents may be copied to at least one other logical volume.