| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a disk device that is able to generate snapshot volumes of multiple generations in a remote site without synchronizing a master volume with a remote master volume, and a method and program for data duplication to the desk device. <P>SOLUTION: The disk device comprises; a second volume to which a first volume data is copied; a third volume storing a snapshot of the first volume; and an I/O processing means which reads data of an address from the third volume if its difference data exists in the third volume. But if its difference data does not exit in the third volume, the means reads data of an address from the first volume if copying data from the first volume to the second volume has not been finished and from the second volume if copying has been finished. <P>COPYRIGHT: (C)2012,JPO&INPIT |
