Method for controlling storage system, and storage control apparatus

• US 7,051,121 B2
• Filed: 04/25/2003
• Issued: 05/23/2006
• Est. Priority Date: 04/26/2002
• Status: Expired due to Fees

• Current Assignee: Hitachi, Ltd.
• Original Assignee: Hitachi, Ltd.
• Inventors: Satoyama, Ai, Tabuchi, Hideo, Yamamoto, Yasutomo, Ohno, Hiroshi, Eguchi, Yoshiaki, Nakano, Toshio, Arai, Kouji, Shimada, Akinobu
• Primary Examiner(s): Huynh, Kim
• Assistant Examiner(s): SORRELL, ERON J
• Application Number:
  US10/424,563
• Publication Number:
  US 20030221077A1
• Time in Patent Office: 1,124 Days
• Field of Search: None
• US Class Current: 710/5
• CPC Class Codes: G06F 12/0866 for peripheral storage systems, e.g. disk cache
• CPC Class Codes: G06F 2212/312 In storage controller
• CPC Class Codes: G06F 3/0607 by facilitating the process of upgrading existing storage systems, e.g. for improving compatibility between host and storage device
• CPC Class Codes: G06F 3/061 Improving I/O performance
• CPC Class Codes: G06F 3/0635 by changing the path, e.g. traffic rerouting, path reconfiguration
• CPC Class Codes: G06F 3/064 Management of blocks
• CPC Class Codes: G06F 3/0659 Command handling arrangements, e.g. command buffers, queues, command scheduling
• CPC Class Codes: G06F 3/0665 at area level, e.g. provisioning of virtual or logical volumes
• CPC Class Codes: G06F 3/067 Distributed or networked storage systems, e.g. storage area networks [SAN], network attached storage [NAS]
• CPC Class Codes: G06F 3/0689 Disk arrays, e.g. RAID, JBOD

Abstract

A method for controlling a storage system including a host computer, and a first and a second storage control apparatuses each receiving a data input/output request from the host computer and executing a data input/output process for a storage device in response to the request, comprises connecting a first communication path between the host computer and the first apparatus; connecting a second communication path between the first apparatus and the second apparatus; receiving by the first apparatus a first data input/output request from the host computer through the first path; when the first apparatus has judged that the first request is not for the first apparatus, transmitting by the first apparatus a second data input/output request corresponding to the first request, to the second apparatus through the second path; and by the second apparatus, receiving the second request and executing a data input/output process corresponding to the second request received.

Claims

1. A method for controlling a storage system including a host computer, and a first and a second storage control apparatuses each having a function for receiving a data input/output request transmitted from said host computer and executing a data input/output process for a storage device in response to said data input/output request received, comprising:

connecting a first communication path between said host computer and said first storage control apparatus;

connecting a second communication path between said first storage control apparatus and said second storage control apparatus;

receiving by said first storage control apparatus a first data input/output request transmitted from said host computer through said first communication path;

when said first storage control apparatus has judged that said first data input/output request is not to be handled by said first storage control apparatus, transmitting by said first storage control apparatus a second data input/output request corresponding to said first data input/output request, to said second storage control apparatus through said second communication path;

receiving, by said second storage control apparatus, said second data input/output request and executing a data input/output process corresponding to said second data input/output request received;

said first and said second storage control apparatuses each organizing one or more logic volume(s) on a storage area provided by a storage device for which said first and said second storage control apparatuses execute respective data input/output processes;

when said first storage control apparatus has received from said host computer a data write-in request of new data to said first logic volume for which said first storage control apparatus executes data input/output processes, transmitting by said first storage control apparatus said data write-in request of the new data to said second storage control apparatus without writing the new data to said first logic volume;

receiving, by said second storage control apparatus, said data write-in request and writing the new data to said second logic volume for which said second storage control apparatus executes data input/output processes;

transmitting by said second storage control apparatus to said first storage control apparatus the storage position of the new data in said second logic volume; and

storing in said first storage control apparatus the storage position in said first logic volume which is the write-in destination of the new data, and the storage position in said second logic volume of the new data transmitted, correlating the two storage positions with each other.

2. A method for controlling a storage system according to claim 1, further comprising:

transmitting by said first storage control apparatus a read-out request concerning the new data to said second storage control apparatus;

receiving the read-out request and transmitting to said first storage control apparatus the new data stored in said second logic volume, by said second storage control apparatus; and

storing in said first storage control apparatus the new data at a storage position of the new data in said first logic volume specified by the correlation.

3. A method for controlling a storage system according to claim 1, said first storage control apparatus having a cache memory used for data write-in to said storage device corresponding to said first logic volume, the method further comprising:

when said first storage control apparatus has received said data write-in request of the new data from said host computer, storing in said first storage control apparatus the new data in said cache memory; and

storing in said first storage control apparatus the new data stored in said cache memory at a storage position in said first logic volume specified by the correlation.

4. A method for controlling a storage system according to claim 1, said first storage control apparatus having a cache memory used for data write-in to said storage device corresponding to said first logic volume, the method further comprising:

when said first storage control apparatus has received the data write-in request of the new data from said host computer, storing by said first storage control apparatus the new data in said cache memory;

checking by said first storage control apparatus whether or not the new data is stored in said cache memory;

if the new data is stored in the cache memory, instead of transmitting the read-out request, storing by said first storage control apparatus the new data stored in said cache memory at a storage position in said first logic volume specified by the correlation; and

if the new data is not stored in the cache memory, by said first storage control apparatus, transmitting the read-out request concerning the new data to said second storage control apparatus and storing the new data transmitted as a response to the read-out request at a storage position in said first logic volume specified by the correlation.

5. A method for controlling a storage system according to claim 3 or 4, further comprising:

determining by said first storage control apparatus whether or not to store the new data in said cache memory depending on the status of use of said cache memory.