| US 7,509,467 B2 | ||
| Storage controller and data management method | ||
| Koji Nagata, Kaisei (Japan); Shoji Kodama, Sagamihara (Japan); Ikuya Yagisawa, Machida (Japan); and Katsuo Mogi, Odawara (Japan) | ||
| Assigned to Hitachi, Ltd., Tokyo (Japan) | ||
| Filed on Jul. 03, 2007, as Appl. No. 11/822,253. | ||
| Application 11/822253 is a continuation in part of application No. 11/358051, filed on Feb. 22, 2006. | ||
| Application 11/358051 is a continuation in part of application No. 11/449668, filed on Jun. 09, 2006. | ||
| Claims priority of application No. 2006-005580 (JP), filed on Jan. 13, 2006; and application No. 2006-032927 (JP), filed on Feb. 09, 2006. | ||
| Prior Publication US 2007/0260833 A1, Nov. 08, 2007 | ||
| This patent is subject to a terminal disclaimer. | ||
| Int. Cl. G06F 12/00 (2006.01) | ||
| U.S. Cl. 711—162 | 18 Claims |
| 1. A storage system comprising a primary storage control device having a first logical volume and a secondary storage control
device having a second logical volume capable of forming a copy pair with the first logical volume,
said primary storage control device further comprising:
a first differential bitmap table for managing positions of updates to the first logical volume due to host accesses;
first snapshot management information for logically reconfiguring a data image of the first logical volume;
a first pool region for storing differential data prior to updating said data image of the first logical volume as a result
of a host access;
a first writing section for writing the data prior to updating to the first pool region when the first logical volume is updated
at a predetermined timing onwards;
a first snapshot updating section for updating the first snapshot management information with information for logically reconfiguring
said data image for the first logical volume occurring at the time of the predetermined timing when the first logical volume
is updated at the predetermined timing onwards;
a first transfer differential bitmap table for managing whether or not update data of the first logical volume has been remote
copied to the second logical volume;
a transfer bitmap table update section for updating the first transfer differential bitmap table by merging bit information
of the first differential bitmap table with the first transfer differential bitmap table; and
a remote copy section for discerning whether each data constituting said data image for the first logical volume at the point
in time of the predetermined timing is in the first logical volume or the first pool region based on the updated first transfer
differential bitmap table, and acquiring data from the discerned party and transmitting the data to the second logical volume,
and
said secondary storage control device further comprising:
a second transfer differential bitmap table for managing positions of updates to the second logical volume due to remote copying;
second snapshot management information for logically reconfiguring a data image of the second logical volume;
a second pool region for storing differential data prior to updating said data image of the second logical volume as a result
of remote copying data to the second logical volume;
a second writing section for writing the data prior to updating to the first pool region when the second logical volume is
updated as a result of remote copying; and
a second snapshot updating section for updating the second snapshot management information with information for logically
reconfiguring said data image for the second logical volume occurring at the time of the predetermined timing when the second
logical volume is updated,
wherein said first snapshot management information is selectively managed by either a first block area or a second block area
which is smaller than the first block area.
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