US 7,523,148 B2
Storage system
Susumu Suzuki, Ooiso (Japan); and Kenji Yamagami, Odawara (Japan)
Assigned to Hitachi, Ltd., Tokyo (Japan)
Filed on May 23, 2005, as Appl. No. 11/134,421.
Application 11/134421 is a continuation of application No. 10/946034, filed on Sep. 22, 2004, granted, now 7,243,116.
Claims priority of application No. 2004-212501 (JP), filed on Jul. 21, 2004.
Prior Publication US 2006/0020754 A1, Jan. 26, 2006
Int. Cl. G06F 12/00 (2006.01); G06F 17/30 (2006.01)
U.S. Cl. 707—204  [707/205] 23 Claims
OG exemplary drawing
 
1. A storage system, comprising:
a controller device coupled to a host computer and controlling to transfer data sent from said host computer to a storage region;
a first logical volume related to said storage region;
a plurality of second logical volumes each being used to store a copy of data stored in said first logical volume;
a third logical volume being used to store a copy of data stored in said first logical volume; and
a plurality of disk drive units having a plurality of disk drives which have said storage region;
wherein said controller device processes the steps of:
receiving a split command sent from said host computer, in accordance with said split command, said controller device starts to change to a first status in which a relationship between said first logical volume and said second logical volumes is split,
receiving a read and/or write command sent from said host computer to said first logical volume after the step of receiving said split command,
copying data related to said read and/or write command from said first logical volume to said third logical volume and then copying said data related to the read and/or write command saved in said third logical volume to said plurality of second logical volumes,
processing said read and/or write command by using said first logical volume, said second logical volumes or said third logical volume, and
replying a reply related to said read and/or write command to said host computer.