Storage area network file system
First Claim
1. A file system on a computer handling read and write requests to a SAN-attached storage device comprising:
- a) a local component that communicates with the SAN-attached storage device over a storage area network;
b) a NAS server that communicates with the SAN-attached storage device over a storage area network;
c) a remote component that communicates with the NAS server over a local area network;
d) an upper level component that communicates with application programs, the upper level component submitting all write requests to the remote component and submitting at least some read requests to the local component.
1 Assignment
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Accused Products
Abstract
A shared storage distributed file system is presented that provides applications with transparent access to a storage area network (SAN) attached storage device. This is accomplished by providing clients read access to the devices over the SAN and by requiring most write activity to be serialized through a network attached storage (NAS) server. Both the clients and the NAS server are connected to the SAN-attached device over the SAN. Direct read access to the SAN attached device is provided through a local file system on the client. Write access is provided through a remote file system on the client that utilizes the NAS server. A supplemental read path is provided through the NAS server for those circumstances where the local file system is unable to provide valid data reads.
Consistency is maintained by comparing modification times in the local and remote file systems. Since writes occur over the remote file systems, the consistency mechanism is capable of flushing data caches in the remote file system, and invalidating metadata and real-data caches in the local file system. It is possible to utilize unmodified local and remote file systems in the present invention, by layering over the local and remote file systems a new file system. This new file system need only be installed at each client, allowing the NAS server file systems to operate unmodified. Alternatively, the new file system can be combined with the local file system.
264 Citations
55 Claims
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1. A file system on a computer handling read and write requests to a SAN-attached storage device comprising:
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a) a local component that communicates with the SAN-attached storage device over a storage area network;
b) a NAS server that communicates with the SAN-attached storage device over a storage area network;
c) a remote component that communicates with the NAS server over a local area network;
d) an upper level component that communicates with application programs, the upper level component submitting all write requests to the remote component and submitting at least some read requests to the local component. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16)
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17. A network of connected computing devices comprising:
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a) a local area network;
b) a storage area network;
c) a SAN-attached device attached to the storage area network;
d) a server computer attached to the local area network and the storage area network;
the server computer receiving file requests across the local area network and further storing real data on the SAN-attached device via the storage area network; and
e) at least one client computer attached to the local area network and the storage area network;
the client computer having;
i) a remote file system in communication with and making file requests to the server computer over the local area network;
ii) a local file system in communication with the SAN-attached device over the storage area network;
iii) an upper level file system serving file requests from an application program operating on the client computer, the upper level file system dividing the file requests from the application program between the remote file system and the local file system. - View Dependent Claims (18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33)
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34. A method for handling file requests for an application, the file requests relating to real data stored on a SAN-attached device, the method comprising:
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a) receiving the file requests from the application;
b) analyzing the file requests to determine whether the request is a local request, and hence should be handled through direct access to the SAN-attached device over a storage area network, or whether the request is a remote request, and should be handled by a server computer accessible by a local area network, with the server computer handling direct access to the SAN-attached device;
c) submitting local requests to the SAN-attached device over the storage area network and then receiving a local response to the file request over the storage area network;
d) submitting remote requests to the server computer over the local area network and then receiving a remote response to the file request over the local area network;
e) relaying the responses to the application. - View Dependent Claims (35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45)
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46. A network of connected computing devices comprising:
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a) a local area network;
b) a storage area network;
c) a SAN-attached device attached to the storage area network;
d) a server computer attached to the local area network and the storage area network;
the server computer receiving file requests across the local area network and further storing and retrieving data on the SAN-attached device via the storage area network; and
e) at least one client computer attached to the local area network and the storage area network;
the client computer having;
i) a remote component in communication with and making file requests to the server computer over the local area network;
ii) a local component in communication with the SAN-attached device over the storage area network;
iii) an upper level component serving file requests from an application program operating on the client computer, the upper level component dividing the file requests from the application program between the remote component and the local component. - View Dependent Claims (47, 48, 49, 50, 51, 52, 53, 54, 55)
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Specification