Managing global cache coherency in a distributed shared caching for clustered file systems
First Claim
1. A method for managing global cache coherency in a distributed shared caching for clustered file systems (CFS) in a computing environment, the method comprising:
- providing the CFS for residing on a cluster of nodes for accessing space of data segments that are shared between the cluster of nodes;
providing, in the CFS, a local cache memory of data segment slots on each of the cluster of nodes and a distributed shared memory (DSM) module, with no internal memory for the data segments on each of the cluster of nodes, wherein the cache memory acts as an external memory;
managing access permissions to an entire space of the data segments by using the DSM module, wherein in response to receiving a request to access one of the data segments;
performing a calculation operation for obtaining most recent contents of the one of the data segments;
determining contents of the one of the data segments are the most recent contents if ownership of the one of the data segments is possessed by a remote DSM module and the request to access one of the data segments is for shared permission and a current permission on the one of the data segments is shared and the one of the data segments exists in the local external cache; and
transporting the most recent contents of the one of the data segments within the response if the response is in a remote external cache and has a valid permission for the one of the data segments otherwise reading from the one of the data segments.
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Abstract
Various embodiments are provided for managing a global cache coherency in a distributed shared caching for a clustered file system (CFS). The CFS manages access permissions to an entire space of data segments by using the DSM module. In response to receiving a request to access one of the data segments, a calculation operation is performed for obtaining most recent contents of one of the data segments. Most recent contents are determined if ownership of the one of the data segments is possessed by a remote DSM module and the request to access one of the data segments is for shared permission and exists in the local external cache. The most recent contents are transported within the response if the response is in a remote external cache and has a valid permission for the one of the data segments otherwise reading from the one of the data segments.
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Citations
18 Claims
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1. A method for managing global cache coherency in a distributed shared caching for clustered file systems (CFS) in a computing environment, the method comprising:
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providing the CFS for residing on a cluster of nodes for accessing space of data segments that are shared between the cluster of nodes; providing, in the CFS, a local cache memory of data segment slots on each of the cluster of nodes and a distributed shared memory (DSM) module, with no internal memory for the data segments on each of the cluster of nodes, wherein the cache memory acts as an external memory;
managing access permissions to an entire space of the data segments by using the DSM module, wherein in response to receiving a request to access one of the data segments;performing a calculation operation for obtaining most recent contents of the one of the data segments; determining contents of the one of the data segments are the most recent contents if ownership of the one of the data segments is possessed by a remote DSM module and the request to access one of the data segments is for shared permission and a current permission on the one of the data segments is shared and the one of the data segments exists in the local external cache; and transporting the most recent contents of the one of the data segments within the response if the response is in a remote external cache and has a valid permission for the one of the data segments otherwise reading from the one of the data segments. - View Dependent Claims (2, 3, 4, 5, 6)
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7. A system for managing global cache coherency in a distributed shared caching for clustered file systems (CFS) in a computing environment, the system comprising:
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a cluster of nodes, the CFS including the cluster of nodes forming a computer cluster, data segments shared between the cluster of nodes, wherein the CFS resides on the cluster of nodes for accessing space of data segments that are shared between the cluster of nodes, a distributed shared memory (DSM) module, with no internal memory for the data segments on each of the cluster of nodes within a node of the cluster of nodes; a plurality of storage devices in communication with the CFS, a local cache memory of data segment slots on each of the cluster of nodes, wherein the cache memory acts as an external memory, a remote cache memory within each of the cluster of nodes, a cache associated with the node, and a processor device having a memory coupled to the processor device for controlling the CFS, wherein the processor device is assigned to the node and the node is in communication with the plurality of storage devices, wherein the processor device; manages access permissions to an entire space of the data segments by using the DSM module, wherein in response to receiving a request to access one of the data segments;
performs a calculation operation for obtaining most recent contents of the one of the data segments,determines contents of the one of the data segments are the most recent contents if ownership of the one of the data segments is possessed by a remote DSM module and the request to access one of the data segments is for shared permission and a current permission on the one of the data segments is shared and the one of the data segments exists in the local external cache, and transports the most recent contents of the one of the data segments within the response if the response is in a remote external cache and has a valid permission for the one of the data segments otherwise reading from the one of the data segments. - View Dependent Claims (8, 9, 10, 11, 12)
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13. A computer program product for managing a global cache coherency in a distributed shared caching for clustered file systems (CFS) using a processor device, the computer program product comprising a non-transitory computer-readable storage medium including computer-readable program code portions stored therein, the computer-readable program code portions comprising:
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a first executable portion that provides the CFS for residing on a cluster of nodes for accessing space of data segments that are shared between the cluster of nodes; a second executable portion that provides, in the CFS, a local cache memory of data segment slots on each of the cluster of nodes and a distributed shared memory (DSM) module, with no internal memory for the data segments on each of the cluster of nodes, wherein the cache memory acts as an external memory; and a third executable portion that manages access permissions to an entire space of the data segments by using the DSM module, wherein in response to receiving a request to access one of the data segments; performs a calculation operation for obtaining most recent contents of the one of the data segments, a fourth executable portion that determines contents of the one of the data segments are the most recent contents if ownership of the one of the data segments is possessed by a remote DSM module and the request to access one of the data segments is for shared permission and a current permission on the one of the data segments is shared and the one of the data segments exists in the local external cache; and a fifth executable portion that transports the most recent contents of the one of the data segments within the response if the response is in a remote external cache and has a valid permission for the one of the data segments otherwise reading from the one of the data segments. - View Dependent Claims (14, 15, 16, 17, 18)
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Specification