Emc Corporation

John A Hilliar

Uday K Gupta

Uresh K Vahalia

John Michael Hayden

Dennis P J Ting

A client computer migrates data objects from a first data store employing a flat namespace to a second data store employing a hierarchical directory-based file system. File storing includes (1) generating a data object (for user data file) and an object identifier which is returned to an application for use in retrieving the user data file; (2) mapping the object identifier to originate a subdirectory name; and (3) sending a write request to the file system to create the named subdirectory and store the data object therein. File retrieving includes (4) sending a read request including the object identifier to the first data store; (5) extracting a user data file from a received data object and returning it to the application; and (6) performing the steps of the file storing to store the data object at the second data store, completing the migration of the data object.

Client-based migrating of data from content-addressed storage to file-based storage

Storing and retrieving user data files includes, in a file storing operation, applying a first mapping (e.g. hash function) to a file identifier to originate a content address in a flat content address space; applying a second mapping (e.g., grouping of digits/characters) to the content address to originate a multi-level directory name usable in a file system; invoking the file system to store the user data file in the named directory. A file retrieving operation includes applying the first mapping to the file identifier to regenerate the content address; applying the second mapping to the regenerated content address to regenerate the directory name; invoking the file system using the regenerated directory name to retrieve the user data file. The method enables a general-purpose network attached storage (NAS) system to store files organized according to a legacy content-addressed storage (CAS) model of existing applications.

Storing data objects from a flat namespace in a hierarchical directory structured file system

A file system that utilizes Virtual Local Area Network (VLAN) addressing and routing schemes to permit implementing multiple networked file system applications in a single data processing system. In particular, a networked file server or data mover has associated with it a mass storage device such as one or more disk drives, as well as one or more Network Interface Cards (NICs). A network interface to the data mover is associated with VLAN identifiers (IDs) such that a VLAN ID can be assigned to each file system. At the physical layer of the data mover, VLAN information is encapsulated and passed up to various higher protocol layers, such as a network layer and/or a transport layer, eventually to a selected file system as dictated by the VLAN ID. The file system application in effect becomes an addressable element of the VLAN. A single data mover can thus be deployed to service multiple groups of end users, as long as the members of each group have different VLAN identifiers for the multiple file systems. The result provides security, access restrictions, and all the other benefits of VLAN protocols that would be obtained by deploying separate data movers for each VLAN, without incurring the acquisition expense and administrative overhead associated with having to purchase and maintain multiple data mover systems.

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Norwood, MA, United States of America

John A Hilliar