Patent ID: 7809907

Claim:
A backup system comprising: a host computer comprising a first coordinator module as an upper layer which is a part of operating system of the host computer, and a first provider module as a lower layer which is provided by a storage vendor to manage a system configuration of the backup system; a backup server comprising a second coordinator module as an upper layer which is a part of operating system of the backup server, and a second provider module as a lower layer which is provided by the storage vendor to manage the system configuration of the backup system; a first storage system coupled to the host computer and having a primary volume that stores data input and output by the host computer; and a second storage system coupled to the backup server and the first storage system and having a first secondary volume that forms a remote copy pair with the primary volume, and a second secondary volume that forms a cascade copy pair with the first secondary volume, wherein the first provider module of the host computer checks whether it is possible to split the cascade copy pair of the first secondary volume and the second secondary volume in accordance with a backup request from the first coordinator module of the host computer, wherein if the cascade copy pair can be split, the first provider module of the host computer registers the primary volume as a subject of backup process, the first coordinator module of the host computer ceases write processing to the primary volume and sends snapshot instruction to the first provider module of the host computer, and the first provider module of the host computer creates a first copy from the primary volume to the first secondary volume, and a second copy from the first secondary volume to the second secondary volume as a snapshot, wherein when detecting completion of the first copy and the second copy, the first provider module of the host computer splits the cascade copy pair and transfers backup information to the first coordinator module of the host system, and wherein if the second coordinator module of the backup server requires at least one backup volume to the second provider module of the backup server, the second provider module of the backup server recognizes the second secondary volume as a first backup volume corresponding to the primary volume, for storing the snapshot of the first secondary volume as of a certain point in time, and cancels a concealment of the first backup volume from the backup server, so that the second coordinator module of the backup server achieves the first backup volume, while the first backup volume is initially concealed from the operating system of the backup server.