Remote copying system with consistency guaranteed between a pair

Abstract

When plural copy groups including pairs exist, remote copying for pairs belonging to copy groups is suspended selectively on a copy group-to-copy group basis, instead of suspending remote copying in all the copy groups at once. A computer system has a host computer, plural first storage systems comprising plural first logical disks, and plural second storage systems comprising plural second logical disks. A first logical disk and a second logical disk paired with the first logical disk, and each pair belongs to either a first copy group or a second copy group. To selectively suspend remote copying on a copy group-to-copy group basis, one of the copy groups is specified first and then pairs belonging to this copy group are designated. The first storage systems comprising first logical disks of the designated pairs suspend remote copy processing for the designated pairs.

1 . A system comprising:
 a host computer;   a plurality of primary storage systems each including primary volumes which are targets of access by the host computer; and   a plurality of secondary storage systems each including secondary volumes,   wherein the host computer is configured to store copy group information defining a first copy group including a plurality of sub-copy groups,   wherein each of the sub-copy groups includes synchronous remote copy pairs from a certain primary storage system to a certain secondary storage system, and does not include a synchronous remote copy pair from other primary storage systems, and   wherein the host computer is configured to:   (A) detect a copy failure of a synchronous copy pair;   (B) specify the first copy group which includes the failed synchronous copy pair;   (C) specify two or more sub-copy groups in the first copy group; and   (D) for each of the sub-copy groups in the first copy group:
 (D1) send a plurality of copy suspension instructions together for a plurality of synchronous remote copy pairs in the each of the sub-copy groups, so that a primary storage system which has received the plurality of copy suspension instructions suspends synchronous remote copy regarding to the synchronous remote copy pairs in the each of the sub-copy groups together. 
   
     
     
         2 . The system according to  claim 1 ,
 wherein the host computer is configured to:   (E) pause writing to primary volumes in the first copy group without pausing of write to another primary volume which is not included in the first copy group, during the process of (D).   
     
     
         3 . A method for operating a system including a host computer, a plurality of primary storage systems each including primary volumes which are targets of access by the host computer, and a plurality of secondary storage systems, each including secondary volumes, said method comprising:
 (A) storing copy group information defining a first copy group including a plurality of sub-copy groups, wherein each of the sub-copy groups includes synchronous remote copy pairs from a certain primary storage system to a certain secondary storage system, and does not include a synchronous remote copy pair from other primary storage systems,   (B) detecting a copy failure of a synchronous copy pair;   (C) specifying the first copy group which includes the failed synchronous copy pair;   (D) specifying two or more sub-copy groups in the first copy group; and   (E) for each of the sub-copy groups in the first copy group sending a plurality of copy suspension instructions together for a plurality of synchronous remote copy pairs in the each of the sub-copy groups, so that a primary storage system which has received the plurality of copy suspension instructions suspends synchronous remote copy regarding to the synchronous remote copy pairs in the each of the sub-copy groups together.   
     
     
         4 . The method according to  claim 3 , further comprising:
 pausing writing to primary volumes in the first copy group without pausing writing to another primary volume which is not included in the first copy group, during the process of (E).   
     
     
         5 . A computer-readable medium having computer-executable instructions for performing a method for operating a system including a host computer, a plurality of primary storage systems, each including primary volumes which are targets of access by the host computer, and a plurality of secondary storage systems each including secondary volumes, said method comprising:
 (A) storing copy group information defining a first copy group including a plurality of sub-copy groups, wherein each of the sub-copy groups includes synchronous remote copy pairs from a certain primary storage system to a certain secondary storage system, and does hot include a synchronous remote copy pair from other primary storage systems,   (B) detecting a copy failure of a synchronous copy pair;   (C) specifying the first copy group which includes the failed synchronous copy pair;   (D) specifying two or more sub-copy groups in the first copy group; and   (E) for each of the sub-copy groups in the first copy group sending a plurality of copy suspension instructions together for a plurality of synchronous remote copy pairs in the each of the sub-copy groups, so that a primary storage system which has received the plurality of copy suspension instructions suspends synchronous remote copy regarding to the synchronous remote copy pairs in the each of the sub-copy groups together.   
     
     
         6 . The computer-readable medium according to  claim 5 , which includes further computer-executable instructions for pausing writing to primary volumes in the first copy group without pausing writing to another primary volume which is not included in the first copy group, during the process of (E).