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Storage system comprising backup function

  • US 7,913,045 B2
  • Filed: 06/20/2007
  • Issued: 03/22/2011
  • Est. Priority Date: 12/28/2006
  • Status: Expired due to Fees
First Claim
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1. A storage system comprising:

  • a storage resource comprising one or more first storage devices;

    a first logical volume formed according to storage space of said storage resource;

    a member for accommodating a removable second storage device selected by a user, said removable second storage device storing disk management information;

    a detector for detecting mounting of said selected removable second storage device in said member, anda backup unit for, when said detector detects mounting of said selected removable second storage device in said member;

    determining whether the management information stored in said selected removable second storage device includes a disk identifier by reading said disk management information from said selected removable second storage device, a presence of said disk identifier in said management information indicating said selected removable second storage device has been previously mounted in said member,in case that said management information includes said disk identifier executing processing (a) and (b);

    (a) backup of data stored in said first logical volume to a second logical volume which is formed according to storage space of a removable second storage device mounted in said member, and which is paired with said first logical volume, and(b) storing, in said storage resource of, a backup generation information element related to what generation of backup a current backup of said first logical volume is,in case that said management information does not include said disk identifier executing processing (d);

    (d) initializing said management information stored in said selected removable second storage device,an I/O processor for receiving, from an external computer provided external of said storage system, an I/O request that designates said first logical volume and writing write target data designated by the I/O request in the first logical volume designated by the I/O request received from the external computer;

    wherein said storage resource stores differential management information elements that correspond with each of a plurality of pairs in which said first logical volume serves as a constituent element,wherein the differential management information elements being information elements that express positions, in said first logical volume, of differential data blocks that are data blocks equivalent to the differential between a second logical volume and said first logical volume which are the constituent elements of pairs corresponding to the differential management information elements,wherein said backup unit, in said (a) processing, specifies the positions of the differential data blocks in said first logical volume on the basis of differential management information elements, of said plurality of differential management information elements, that correspond with a target pair which constitutes a pair in which the second logical volume of the removable second storage device mounted in said member serves as a constituent element, and backs up the differential data blocks in the specified positions to positions of the second logical volume that correspond to the specified positions,wherein said storage resource further stores a pair state that corresponds to each plurality of pairs in which said first logical volume serves as a constituent element,wherein said I/O processor, when the pair state of the pairs in which said first logical volume serves as a constituent element is a first-type status and, whenever a data block of said write target data is written in said first logical volume, updates the differential management information elements that correspond to the pair to a state of existence of differential data blocks in the write destination position,wherein said backup unit initializes backup after updating the pair state that corresponds to said target pair to a second-type status and, when backup is completed, updates the differential management information elements that correspond with said target pair to a state of absence of differential data blocks, and updates the pair state that corresponds to said target pair to a first-type status, andwherein said backup unit, in said (b) processing, after updating the pair state that corresponds to said target pair to said first-type status, further stores in said removable second storage device pair management information elements that constitute information pertaining to said target pair, following which, when said removable second storage device is demounted from said member and the demounted removable second storage device or another storage device selected by said user has been newly mounted in said member, in said (a) processing, specifies differential management information elements that correspond to the pair management information elements of the removable second storage device mounted in said member.

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