Emc Corporation

Dropbox, Inc.

Stephen A Rago

James Theodore Compton

Uday K Gupta

Stephen A Fridella

Surrendranath R Doohkan

Nikolay Popov

Christopher H Stacey

Gustavo M Gonzalez

Eyal Zimran

Jerald W Gross

Gordon J Harris

Augustine Amegadzie

Alex Jeffrey Palkovic

Aleksandr Bakhturin

Jessica Kenney

Timothy H Williams

Techniques for an online cache migration in a distributed caching system using a hybrid migration process include an application server in a network environment determining that an online cache migration from a source cache to a target cache is running. Based on this, the application server selectively mirroring writes to the source cache in the target cache. Meanwhile, an external migration controller migrates the cache from the source cache to the target cache in a way that does not require the external migration controller or the application server to synchronize their concurrent access to the source and target caches yet still allows the application server to read, write, and delete cache data in the source cache during the migration.

Online cache migration in a distributed caching system using a hybrid migration process

An improved policy enforcement architecture includes several components that improve the performance of policy enforcement in a hierarchical storage environment. A File System Query instruction permits a richer set of queries to be expressed by a policy engine, thereby permitting more complex policies to be implemented with ease. The File System result is generated at the file server, and only files of interest are forwarded to the policy engine. The file system query advantageously may be applied against a pre-generated index having one more characterizing attributes to further reduce the processing required to retrieve policy data. An Index Build instruction, added to a programming interface, allows a policy engine generate the characterizing indices in advance of use. Index maintenance techniques maintain consistency between the index and the file system to ensure that the policy can be enforced using accurate file information.

Apparatus and method for maintaining a file system index

A hierarchical storage system is constructed from file servers and a policy engine server by building upon a file migration service. Offline attributes are added to file system inodes in a primary file server, file system parameters are added in the primary server, an offline read access method field is added to a connection database, and the primary file server is programmed to use these attributes and parameters for selecting a particular method (such as a partial read migration or a pass through read method) for read access to an offline file. In this fashion, the primary file server is provided with flexibility for selecting a particular one of a number of migration methods depending on various conditions, in order to improve the trade-off between the cost of storage and delay in file access.

Selection of migration methods including partial read restore in distributed storage management

File system query and method of use

Apparatus and method for building a file system index

The invention provides a way for computer applications to parse the operating system's file system format without embedding direct knowledge of the format in the applications themselves. By making a file system self-describing, applications running locally on the same computer, or remotely on another computer, can interpret file system data structures if they can access the disk containing the file system. Storage Area Networks (SANs) present a paradigm where multiple computer systems can see the same set of disk resources. This, combined with the invention of self-describing file systems, makes it possible to build applications that are more intelligent and perform better than their counterparts that either embed knowledge of a file system or rely on a file system driver to interpret the structure on behalf of the applications.

Self-describing file system

A method and system for managing storage resources associated with a network having at least one storage resource coupled to at least one server and at least one client over at least one data path. The method and system includes servers managing the storage resource over the data path, and clients directing I/O requests to the storage resources and redirecting I/O requests to the servers upon the detection of a failure condition.

Distributed storage resource management in a storage area network

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Berkely Heights, NJ, United States of America

Stephen A Rago