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Method and system for maintaining concurrent data access during device upgrade

  • US 5,701,429 A
  • Filed: 08/16/1996
  • Issued: 12/23/1997
  • Est. Priority Date: 06/20/1994
  • Status: Expired due to Fees
First Claim
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1. In a data storage system including a plurality of direct access storage devices, each having a fixed number of unique addresses and the same number of logical volumes, and a storage controller being connected to each of the plurality of direct access storage devices, a method of maintaining concurrent data access while upgrading at least one of said plurality of direct access storage devices containing data and coupled to a host computer via a channel comprising the steps of:

  • responsive to receipt of a request to upgrade said at least one of said plurality of direct access storage devices data over a channel, copying said data to another one of said plurality of direct access storage devices having no data;

    logically mapping said fixed number of unique addresses of said at least one of said plurality of direct access storage devices to said another one of said plurality of direct access storage devices to which said data has been copied;

    removing said at least one of said plurality of direct access storage devices;

    upgrading said at least one of said plurality of direct access storage devices with a direct access storage device having a greater number of unique addresses;

    reconfiguring said storage controller to accommodate said greater number of unique addresses;

    recopying said data to said upgraded direct access storage device into said greater number of unique addresses; and

    logically remapping said unique addresses of said another of said plurality of direct access storage devices to said greater number of unique addresses of said upgraded direct access storage to which said data has been recopied.

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