Methods to perform disk writes in a distributed shared disk system needing consistency across failures
First Claim
1. A method for managing caches in a system with multiple caches that contain different copies of a data item, comprising the steps of:
- modifying the data item in a first node of said multiple caches to create a modified data item;
sending the modified data item from said first node to a second node of said multiple caches without durably storing the modified data item from said first node to persistent storage;
after said modified data item has been sent from said first node to said second node, said first node sending a request to a master of said data item for writing said data item to persistent storage; and
in response to said request, said master coordinating with said multiple caches to cause said data item to be written to persistent storage.
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Accused Products
Abstract
Techniques are provided for managing caches in a system with multiple caches that may contain different copies of the same data item. Specifically, techniques are provided for coordinating the write-to-disk operations performed on such data items to ensure that older versions of the data item are not written over newer versions, and to reduce the amount of processing required to recover after a failure. Various approaches are provided in which a master is used to coordinate with the multiple caches to cause a data item to be written to persistent storage. Techniques are also provided for managing checkpoints associated with the caches, where the checkpoints are used to determine the position at which to begin processing recovery logs in the event of a failure.
89 Citations
46 Claims
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1. A method for managing caches in a system with multiple caches that contain different copies of a data item, comprising the steps of:
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modifying the data item in a first node of said multiple caches to create a modified data item; sending the modified data item from said first node to a second node of said multiple caches without durably storing the modified data item from said first node to persistent storage; after said modified data item has been sent from said first node to said second node, said first node sending a request to a master of said data item for writing said data item to persistent storage; and in response to said request, said master coordinating with said multiple caches to cause said data item to be written to persistent storage. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23)
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24. A computer-readable medium carrying instructions for managing caches in a system with multiple caches that contain different copies of a data item, the instructions comprising instructions for performing the steps of:
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modifying the data item in a first node of said multiple caches to create a modified data item; sending the modified data item from said first node to a second node of said multiple caches without durably storing the modified data item from said first node to persistent storage; after said modified data item has been sent from said first node to said second node, said first node sending a request to a master of said data item for writing said data item to persistent storage; and in response to said request, said master coordinating with said multiple caches to cause said data item to be written to persistent storage. - View Dependent Claims (25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46)
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Specification