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Methods to perform disk writes in a distributed shared disk system needing consistency across failures

  • US 7,930,278 B2
  • Filed: 02/20/2007
  • Issued: 04/19/2011
  • Est. Priority Date: 02/13/1998
  • Status: Expired due to Term
First Claim
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1. A method for managing caches in a system with multiple caches that may contain different copies of a data item, comprising the steps of:

  • modifying the data item in a first cache to create a modified version of the data item;

    wherein said data item is one of a plurality of data items stored in persistent storage;

    wherein each data item of the plurality of data items is mastered by a master;

    wherein the master for each data item of the plurality of data items maintains information about said each data item to coordinate writing of said each data item to persistent storage;

    writing the modified version of the data item to persistent storage;

    in response to writing the modified version of the data item to persistent storage, performing the steps of;

    a node associated with the first cache determining whether any other cache in said multiple caches had created a dirty version of said data item; and

    if any other cache in said multiple caches had created a dirty version of said data item, then the node associated with the first cache informing the master of said data item that said modified version of the data item has been written to persistent storage; and

    if no other cache in said multiple caches had created a dirty version of said data item, then the step of writing the modified version of the data item is performed without informing said master that said modified version of the data item has been written to persistent storage;

    wherein the method is performed by one or more computing devices.

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