Stephen A Fridella

7412496, Aug 12, 2008

Aug 22, 2003

10/645976

Stephen A Fridella - Newton MA, US
Gang Ma - Shrewsbury MA, US
Xiaoye Jiang - Shrewsbury MA, US
Sorin Faibish - Newton MA, US
Rui Liang - Natick MA, US

EMC Corporation - Hopkinton MA

G06F 15/16
G06F 15/173

709219, 709203, 709217, 709225, 709229

To permit multiple unsynchronized processors to update the file-modification time attribute of a file during concurrent asynchronous writes to the file, a primary processor having a clock manages access to metadata of the file. A number of secondary processors service client request for access to the file. Each secondary processor has a timer. When the primary processor grants a range lock upon the file to a secondary, it returns its clock time (m). Upon receipt, the secondary starts a local timer (t). When the secondary modifies the file data, it determines a file-modification time that is a function of the clock time and the timer interval, such as a sum (m+t). When the secondary receives an updated file-modification time (mp) from the primary, if mp>m+t, then the secondary updates the clock time (m) to (mp) and resets its local timer.

7617216, Nov 10, 2009

Sep 7, 2005

11/220780

Stephen A. Fridella - Belmont MA, US
Xiaoye Jiang - Shrewsbury MA, US
Sorin Faibish - Newton MA, US
John Forecast - Newton MA, US

EMC Corporation - Hopkinton MA

G06F 17/30

707 10

A file server system has a cluster of server computers that share access to a file system in shared storage. One of the server computers has primary responsibility for management of access to the file system. In order to reduce the possibility of primary server overload when a large number of the clients happen to concurrently access the same file system, most metadata processing operations are offloaded to secondary server computers. This also facilitates recovery from failure of a primary server computer since only a fraction of the ongoing metadata operations of a primary server computer is interrupted by a failure of the primary server computer. For example, a secondary data mover may truncate, delete, create, or rename a file in response to a client request.

7653832, Jan 26, 2010

May 8, 2006

11/382233

Sorin Faibish - Newton MA, US
Stephen A. Fridella - Belmont MA, US
Uday K. Gupta - Westford MA, US
Xiaoye Jiang - Shrewsbury MA, US
Peter C. Bixby - Westborough MA, US

EMC Corporation - Hopkinton MA

G06F 11/00

714 7

A cached disk array includes a disk storage array, a global cache memory, disk directors coupling the cache memory to the disk storage array, and front-end directors for linking host computers to the cache memory. The front-end directors service storage access requests from the host computers, and the disk directors stage requested data from the disk storage array to the cache memory and write new data to the disk storage. At least one of the front-end directors or disk directors is programmed for block resolution of virtual logical units of the disk storage, and for obtaining, from a storage allocation server, space allocation and mapping information for pre-allocated blocks of the disk storage, and for returning to the storage allocation server requests to commit the pre-allocated blocks of storage once data is first written to the pre-allocated blocks of storage.

7676514, Mar 9, 2010

May 8, 2006

11/382193

Sorin Faibish - Newton MA, US
Stephen A. Fridella - Belmont MA, US
Uday K. Gupta - Westford MA, US
Xiaoye Jiang - Shrewsbury MA, US

EMC Corporation - Hopkinton MA

G06F 7/00
G06F 17/00
G06F 13/00

707646, 707649, 707655, 711162

A primary processor manages metadata of a production dataset and a snapshot copy, while a secondary processor provides concurrent read-write access to the primary dataset. The secondary processor determines when a first write is being made to a data block of the production dataset, and in this case sends a metadata change request to the primary data processor. The primary data processor commits the metadata change to the production dataset and maintains the snapshot copy while the secondary data processor continues to service other read-write requests. The secondary processor logs metadata changes so that the secondary processor may return a “write completed” message before the primary processor commits the metadata change. The primary data processor pre-allocates data storage blocks in such a way that the “write anywhere” method does not result in a gradual degradation in I/O performance.

7676628, Mar 9, 2010

Mar 31, 2006

11/394768

James T. Compton - Durham NC, US
Uday K. Gupta - Westford MA, US
Sorin Faibish - Newton MA, US
Roy E. Clark - Hopkinton MA, US
Stephen Fridella - Belmont MA, US
Xiaoye Jiang - Shrewsbury MA, US

EMC Corporation - Hopkinton MA

G06F 12/00
G06F 13/00

711114, 711148, 711202

Methods, systems, and computer program products for providing access to shared storage by a plurality of nodes are disclosed. According to one method, at a node of a plurality of nodes sharing access to a disk array, an application input/output (I/O) operation and whether sufficient space in the disk array has been mapped at the node for the I/O operation are detected. In response to detecting that sufficient space in the disk array has not been mapped at the node for the I/O operation, a map for the I/O operation including physical disk access information is requested and obtained from a server. The physical disk access information included within the map for the application I/O operation obtained from the server is used to perform the I/O operation by accessing the disk array without intervention by the server.

7783615, Aug 24, 2010

Sep 30, 2005

11/241132

James T. Compton - Durham NC, US
Stephen A. Fridella - Belmont MA, US
Uday K. Gupta - Westford MA, US
Nikolay Popov - Wayland MA, US
Stephen A. Rago - Warren NJ, US

EMC Corporation - Hopkinton MA

G06F 7/00

707694, 707636, 707665, 707812, 707826, 707830

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.

7805416, Sep 28, 2010

Sep 30, 2005

11/241053

James T. Compton - Durham NC, US
Stephen A. Fridella - Belmont MA, US
Uday K. Gupta - Westford MA, US
Nikolay Popov - Wayland MA, US
Stephen A. Rago - Warren NJ, US

EMC Corporation - Hopkinton MA

G06F 7/00

707694, 707622, 707764, 707770, 707781

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.

7822728, Oct 26, 2010

Nov 8, 2006

11/557941

Richard G. Chandler - West Hartford CT, US
Stephen A. Fridella - Newton MA, US
Sorin Faibish - Newton MA, US
Uday K. Gupta - Westford MA, US
Xiaoye Jiang - Shrewsbury MA, US

EMC Corporation - Hopkinton MA

G06F 7/00
G06F 17/00

707704, 707700, 707999008

A read-write access to a file in a file server includes an initial metadata access step, an asynchronous read or write of file data, and a metadata commit step. In order to parallelize access to a range locking database, an inode and indirect file block mapping database, and a pre-allocation data base, operations are pipelined within the metadata access step and also within the metadata commit step. The pipelined operations within the metadata access step include a first stage of range locking, a second stage of reading block mapping metadata, and a third stage of reading and updating a pre-allocation map for write access. The pipelined operations within the metadata commit step include a first stage of releasing range locks, a second stage of accessing old block metadata for write access, and a third stage of updating metadata and flushing the pre-allocation map for write access.