Storage apparatus and data management method

Abstract

A storage apparatus includes storage devices of a plurality of types of varying performance, and a control unit which manages each of storage areas provided by the storage devices of the plurality of types by means of storage tiers of a plurality of different types, and assigns the storage areas in page units to a virtual volume from any of the storage tiers among the storage tiers of the plurality of types. If the data I/O request is received from the host, the control unit assigns storage areas in page units from the uppermost storage tier to the target areas of the virtual volume corresponding to the I/O request. The control unit changes the page unit storage area assignment to predetermined areas of the virtual volume from an upper storage tier to a lower storage tier in accordance with the speed of processing of the data I/O request.

1 . A storage apparatus coupled to a host computer, the storage apparatus comprising:
 a plurality of storage devices classified into tiers according to reliability attribute and/or performance attribute of the storage devices; and   a controller configured to:   provide the host computer with virtual volume including a plurality of virtual area; and   allocate a storage area of the plurality of storage devices to a virtual area, to which the storage area is not allocated, of the virtual volume in response to a write request to the virtual area from the host computer,   wherein the controller is configured to:   determine whether allocation of a first virtual area, to which a storage area of a second tier is allocated, of the plurality of virtual area is to be changed to a storage area of a first tier when the controller receives the access request to the first virtual area; and   change the allocation of the first virtual area from the second tier to the first tier when needed, and   wherein the controller is configured to:   determine whether allocation of a second virtual area, to which a storage area of the first tier is allocated, of the plurality of virtual area is to be changed to a storage area of the second tier when the unallocated capacity of the first tier falls below a threshold; and   change the allocation of the first virtual area to the storage area of the second tier when needed.   
     
     
         2 . The storage apparatus according to  claim 1 ,
 wherein the first tier has higher reliability attribute and/or higher performance than the second tier.   
     
     
         3 . The storage apparatus according to  claim 2 ,
 wherein the first tier has the highest reliability attribute and/or the highest performance attribute among tier.   
     
     
         4 . The storage apparatus according to  claim 1 ,
 wherein the controller is configured to determine whether allocation of the second virtual area is changed from the first tier to the second tier according to an access frequency of the second virtual area.   
     
     
         5 . A method relating to a storage apparatus coupled to a host computer, the storage apparatus comprising a plurality of storage devices classified into tiers according to reliability attribute and/or performance attribute of the storage devices and a controller, the method comprising
 providing, by the controller, the host computer with virtual volume including a plurality of virtual area; and   allocating, by the controller, a storage area of the plurality of storage devices to a virtual area, to which the storage area is not allocated, of the virtual volume in response to a write request to the virtual area from the host computer,   determining, by the controller, whether allocation of a first virtual area, to which a storage area of a second tier is allocated, of the plurality of virtual area is to be changed to a storage area of a first tier when the controller receives the access request to the first virtual area; and   changing, by the controller, the allocation of the first virtual area from the second tier to the first tier when needed, and   determining, by the controller, whether allocation of a second virtual area, to which a storage area of the first tier is allocated, of the plurality of virtual area is to be changed to a storage area of the second tier when the unallocated capacity of the first tier falls below a threshold; and   changing, by the controller, the allocation of the first virtual area to the storage area of the second tier when needed.   
     
     
         6 . The method according to  claim 5 ,
 wherein the first tier has higher reliability attribute and/or higher performance than the second tier.   
     
     
         7 . The method according to  claim 6 ,
 wherein the first tier has the highest reliability attribute and/or the highest performance attribute among tier.   
     
     
         8 . The method according to  claim 5 , further comprising
 determining, by the controller, whether allocation of the second virtual area is changed from the first tier to the second tier according to an access frequency of the second virtual area.