Storage controller and method for controlling the same

Abstract

A storage controller facilitating extending storage capacity while suppressing investment related to storage capacity is provided. System configuration information, including content of a definition of a virtual volume having a storage capacity that is larger than a real storage capacity including the storage capacity of a storage device unit, and content of a definition of at least one of a real volume formed by dividing the real storage capacity, and a pool area, is stored. Based on the system configuration information, relevant data is written to or read from an address position in the storage device unit in response to a data input/output request from the host system designating an address in the real volume, and data is written to or read from the pool area in response to a data input/output request from the host system designating an address in the virtual volume other than the real volume.

1 . A storage controller for controlling data input/output between a host system and a storage device unit that stores data, the storage controller comprising:
 a control unit managing a virtual volume to be provided to the host system, a real volume, a pool area and a plurality of entries of data storing in the pool area,   wherein the real volume is assigned to a first part of the virtual volume and is set as a logical volume for performing read/write operations from/to the storage device unit, and a second part of the virtual volume is not yet assigned to the real volume,   wherein, in response to a data input request from the host system to an address of the second part of the virtual volume, the control unit allocates the address of the second part of the virtual volume to a storage area in the pool area transparently to the host system, according to a method in which the allocated storage area is reserved sequentially from a top address of the pool area, and stores data of the data input request to the allocated storage area in the pool area, and   wherein the control unit copies data stored in the pool area to the real volume transparently to the host system and cancels an entry of the data stored in the pool area.   
   
   
       2 . The storage controller according to  claim 1 ,
 wherein the virtual volume is provided, to the host system, using a storage capacity larger that a real storage capacity of the real volume, and   wherein the control unit communicates, to the host system, the storage capacity of the virtual volume in response to a storage capacity request from the host system.   
   
   
       3 . The storage controller according to  claim 1 , wherein the control unit confirms a remaining amount of the pool area by calculating based on an address for a last effective entry of data storing in the pool area. 
   
   
       4 . The storage controller according to  claim 3 , wherein the control unit communicates the confirmed remaining amount of the pool area to a management console coupled to the storage controller. 
   
   
       5 . A storage system coupled to a host system, the storage system comprising:
 a storage device unit that stores data; and   a control unit managing a virtual volume to be provided to the host system, a real volume, a pool area and a plurality of entries of data storing in the pool area,   wherein the real volume is assigned to a first part of the virtual volume and is set as a logical volume for performing read/write operations from/to the storage device unit, and a second part of the virtual volume is not yet assigned to the real volume,   wherein, in response to a data input request from the host system to an address of the second part of the virtual volume, the control unit allocates the address of the second part of the virtual volume to a storage area in the pool area transparently to the host system, according to a method in which the allocated storage area is reserved sequentially from a top address of the pool area, and stores data of the data input request to the allocated storage area in the pool area, and   wherein the control unit copies data stored in the pool area to the real volume transparently to the host system and cancels an entry of the data stored in the pool area.   
   
   
       6 . The storage system according to  claim 5 ,
 wherein the virtual volume is provided, to the host system, using a storage capacity larger than a real storage capacity of the real volume, and   wherein the control unit communicates, to the host system, the storage capacity of the virtual volume in response to a storage capacity request from the host system.   
   
   
       7 . The storage system according to  claim 5 , wherein the control unit confirms a remaining amount of the pool area by calculating based on an address for a last effective entry of data storing in the pool area. 
   
   
       8 . The storage system according to  claim 7 , wherein the control unit communicates the confirmed remaining amount of the pool area to a management console coupled to the storage system. 
   
   
       9 . A data control method for a storage controller for controlling data input/output between a host system and a storage device unit that stores data, the data control method comprising:
 managing a virtual volume to be provided to the host system, a real volume, a pool area and a plurality of entries of data storing in the pool area,   wherein the real volume is assigned to a first part of the virtual volume and is set as a logical volume for performing read/write operations from/to the storage device unit, and a second part of the virtual volume is not yet assigned to the real volume;   allocating, in response to a data input request from the host system to an address of the second part of the virtual volume, the address of the second part of the virtual volume to a storage area in the pool area transparently to the host system, according to a method in which the allocated storage area is reserved sequentially from a top address of the pool area;   storing data of the data input request to the allocated storage area in the pool area; and   copying data stored in the pool area to the real volume transparently to the host system and canceling an entry of the data stored in the pool area.   
   
   
       10 . The data control method according to  claim 9 ,
 wherein the virtual volume is provided, to the host system, using a storage capacity larger than a real storage capacity of the real volume, and   wherein the data control method further comprises:   communicating, to the host system, the storage capacity of the virtual volume in response to a storage capacity request from the host system.   
   
   
       11 . The data control method according to  claim 9 , further comprising:
 confirming a remaining amount of the pool area by calculating based on an address for a last effective entry of data storing in the pool area.   
   
   
       12 . The data control method according to  claim 11 , further comprising:
 communicating the confirmed remaining amount of the pool area to a management console coupled to the storage controller.