Clustered filesystem
First Claim
1. A cluster of computer systems, comprising:
- storage devices storing at least one mirrored data volume with at least two mirror legs;
a storage area network coupled to said storage devices; and
computer system nodes, coupled to said storage area network, sharing direct read/write access to said storage devices and maintaining mirror consistency during normal operation and upon failure of at least one of said storage devices or at least one of said computer system nodes, while continuing to accept access requests to the mirrored data volume.
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Accused Products
Abstract
A cluster of computer system nodes share direct read/write access to storage devices via a storage area network using a cluster filesystem. Version information about subsystems is acquired by a leader node when forming a cluster membership and distributed to all nodes in the cluster to enable proper messaging during operation. Access to files on the storage devices is arbitrated by the cluster filesystem using tokens. Upon detection of a change in location of the metadata server, client nodes waiting for a token are interrupted to check on the status of at least one of data and node availability. The cluster operating system maintains consistency of a mirrored data volume by automatically ensuring replication of a mirror leg while continuing to accept access requests to the mirrored data volume.
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Citations
12 Claims
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1. A cluster of computer systems, comprising:
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storage devices storing at least one mirrored data volume with at least two mirror legs;
a storage area network coupled to said storage devices; and
computer system nodes, coupled to said storage area network, sharing direct read/write access to said storage devices and maintaining mirror consistency during normal operation and upon failure of at least one of said storage devices or at least one of said computer system nodes, while continuing to accept access requests to the mirrored data volume.
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2. A method of maintaining mirror consistency of data volumes in a cluster of computer system nodes sharing direct read/write access to storage devices via a storage area network, comprising:
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automatically ensuring replication of a mirror leg in response to detection that a failed process was writing to a mirrored data volume;
accepting access requests to the mirrored data volume while reading data from an intact mirror leg and writing the data back to the mirrored data volume; and
processing the access requests that do not interfere with the creation of a replacement mirror leg while postponing processing of interfering access requests until there is no interference. - View Dependent Claims (3, 4, 5)
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6. At least one computer readable medium storing at least one program embodying a method of maintaining mirror consistency of data volumes in a cluster of computer systems sharing direct read/write access to storage devices via a storage area network, said method comprising:
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automatically ensuring replication of a mirror leg in response to detection that a failed process was writing to a mirrored data volume;
accepting access requests to the mirrored data volume while reading data from an intact mirror leg and writing the data back to the mirrored data volume; and
processing the access requests that do not interfere with the creation of a replacement mirror leg while postponing processing of interfering access requests until there is no interference.
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7. A method of establishing a new cluster membership of computer system nodes sharing direct read/write access to storage devices via a storage area network and a cluster operating system, comprising:
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transmitting version tags for at least one subsystem of the cluster operating system from each node of a prospective membership to a leader node when establishing the nodes available for cluster membership; and
transmitting version information for all of the nodes with a proposed cluster membership from the leader node to all other nodes in the proposed cluster membership. - View Dependent Claims (8)
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9. At least one computer readable medium storing at least one program embodying a method of establishing a new cluster membership of computer system nodes sharing direct read/write access to storage devices via a storage area network and a cluster operating system, comprising:
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transmitting version tags for at least one subsystem of the cluster operating system from each node of a prospective membership to a leader node when establishing the nodes available for cluster membership; and
transmitting version information for all of the nodes with a proposed cluster membership from the leader node to all other nodes in the proposed cluster membership.
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10. A method of operating a cluster of computer system nodes sharing direct read/write access to storage devices via a storage area network, comprising:
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requesting a token by a client node from a metadata server node for a file prior to performing a required access to the file;
waiting for a response to said requesting;
holding the token at the client node upon receipt from the metadata server node;
releasing the token at the client node upon completion of the required access to the file; and
interrupting said waiting to check on status of at least one of data and node availability, in response to detection of a change in location of the metadata server.
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11. At least one computer readable medium storing at least one program embodying a method of operating a cluster of computer system nodes sharing direct read/write access to storage devices via a storage area network, said method comprising:
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requesting a token by a client node from a metadata server node for a file prior to performing a required access to the file;
waiting for a response to said requesting;
holding the token at the client node upon receipt from the metadata server node;
releasing the token at the client node upon completion of the required access to the file; and
interrupting said waiting to check on status of at least one of data and node availability, in response to detection of a change in location of the metadata server.
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12. A cluster of computer systems, comprising:
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storage devices storing at least one file;
a storage area network coupled to said storage devices;
at least one metadata server node, coupled to said storage area network metadata client nodes, coupled to said storage area network, sharing direct read/write access to said storage devices by sending a token request from said at least one metadata server node for the at least one file prior to performing a required access to the at least one file, waiting for a response to the token request, holding at least one token upon receipt from said at least one metadata server node, releasing the at least one token upon completion of the required access to the file and interrupting the waiting to check on status of at least one of data and node availability, in response to detection of a change in location of said at least one metadata server node.
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Specification