Volume providing system and method

Abstract

A host computer HA 1 or the like is provided with a target program 3 that receives the provision of logical volumes 212 , a volume interface program 12 A that provides an interface for the logical volumes 212 to the target program 3 , and a volume filter program 12 B that selects one logical volume from the copying source volume 212 A and copying destination volume 212 B, and provides the selected logical volume to the target program 3 via the volume interface program 12 A.

1 . (canceled)  
   
   
       2 . A computer system configured for data communication with a data storage device configured to provide a first data volume and a second data volume, comprising: 
 a data processor; and    memory for storing first stored program code that is executable by the data processor and second stored program code that is executable by the data processor,    wherein the first stored program code is configured to operate the data processor to: 
 execute a first instance of the second stored program code; and  
 execute a second instance of the second stored program code,  
   wherein during a first operating mode, first I/O requests containing a data volume identifier provided by an application program are serviced by execution only of the first instance of the second program code to: 
 receive the first I/O requests; and  
 access the first data volume to service the first I/O requests,  
   wherein during a second operating mode, second I/O request containing the same data volume identifier provided by the application program are serviced by execution of both the first instance of the second program code and the second instance of the second program including: 
 execution of the first instance of the second program code to receive the second I/O requests;  
 execution of the first instance of the second program code to send access requests related to the second I/O requests to the second instance of the second program code; and  
 execution of the second instance of the second program code to access the second data volume to service the second I/O requests.  
   
   
   
       3 . The computer system of  claim 2  wherein in the second operating mode, execution of the second instance of the second program code further sends, to the first instance of the second program code, information relating to accessing of the second data volume.  
   
   
       4 . The computer system of  claim 2  wherein the data storage device further provides a plurality of data volumes including the first data volume and the second data volume, wherein the memory includes a pool management table comprising information indicative, for each data volume, whether it is part of a volume pair with another data volume.  
   
   
       5 . The computer system of  claim 4  wherein the first stored program code assigns the first data volume to the first instance of the second stored program code and assigns the second data volume to the second instance of the second stored program code, based at least on information comprising the pool management table.  
   
   
       6 . The computer system of  claim 2  wherein the data storage device further provides a plurality of data volumes including the first data volume and the second data volume, wherein the memory includes a pair management table comprising information indicative of pairs of data volumes that are in a paired state, wherein the first stored program code assigns the first data volume to the first instance of the second stored program code and assigns the second data volume to the second instance of the second stored program code, based at least on information comprising the pool management table.  
   
   
       7 . A method in a computer system accessing a data storage device configured to provide a first data volume and a second data volume, comprising: 
 operating the computer system in a first mode including executing a first process, wherein the first process performs steps of: 
 receiving a first I/O operation from an application program; and  
 servicing the first I/O operation by accessing the first data volume,  
 wherein the first I/O instruction includes a device identifier provided by the application program; and  
   operating the computer system in a second mode including executing a second process in addition to the first process, wherein: 
 the first process performs steps of: 
 receiving a second I/O operation from the application program, the second I/O operation including the device identifier as in the first I/O operation; and  
 communicating one or more data access requests to the second process based on the second I/O operation;  
 
 the second process performs a step of servicing the second I/O operation by accessing the second data volume in accordance with the one or more data access requests received from the first process.  
   
   
   
       8 . The method of  claim 7  wherein in the second process further performs a step of communicating to the first process information relating to accessing of the second data volume.  
   
   
       9 . The method of  claim 7  wherein the data storage device further provides a plurality of data volumes including the first data volume and the second data volume, wherein the method further comprises managing a pool management table comprising information indicative, for each data volume, whether it is part of a volume pair with another data volume.  
   
   
       10 . The method of  claim 9  wherein the first process accesses the first data volume and the second process accesses the second data volume, based at least on information comprising the pool management table.  
   
   
       11 . The method of  claim 2  wherein the data storage device further provides a plurality of data volumes including the first data volume and the second data volume, wherein the method further comprises managing a pair management table comprising information indicative of pairs of data volumes that are in a paired state, wherein the first process accesses the first data volume and the second process accesses the second data volume, based at least on information comprising the pool management table.