Ishay Kedem

6341333, Jan 22, 2002

Sep 15, 1999

09/396218

Moshe Schreiber - Brookline MA
Ishay Kedem - Brookline MA
Yuval Ofek - Framingham MA
Natan Vishlitzky - Brookline MA
Eli Shagam - Brookline MA

EMC Corporation - Hopkinton MA

G06F 1200

711114, 711167, 711170, 709105, 714 7

Load balancing of activities on physical disk storage devices is accomplished by monitoring reading and writing operations to blocks of contiguous storage locations, such as logical volumes on the physical disk storage devices to obtain disk utilization information. The disk utilization information provides a selection of one block pair. After testing to determine any adverse effect of making that change, an exchange is made to more evenly distribute the loading on individual physical disk storage devices. The exchange involves the use of a pair of specially configured logical volumes that receive copies of the data to be exchanged, allow a reconfiguration of the blocks in the block pair and the transfer of the data back to the other blocks in the block pair to effect the exchange.

6363385, Mar 26, 2002

Jun 29, 1999

09/342608

Ishay Kedem - Brookline MA
Hana Moreshet - Framingham MA
Douglas E. LeCrone - Hopkinton MA
Bruce A. Pocock - Titusville FL

EMC Corporation - Hopkinton MA

G06F 1730

707 10, 707201, 707202, 707204

A method for copying a data file from a source device to a destination device. In response to a copy command from a requesting host application identifying the source file and the storage locations in a destination, an extents track is formed to establish an environment in which the file will be copied. The calling system receives an immediate response that the copy operation is complete even though no data has been copied. Application programs may access the file in either the source or the destination. A copy program transfers the file on a track-by-track basis to the destination storage locations. Procedures assure that any data access to a particular track in either the source or destination by any application prior to the transfer of that track are accommodated to maintain data integrity.

6389511, May 14, 2002

Aug 9, 2000

09/634967

Ishay Kedem - Brookline MA

EMC Corporation - Hopkinton MA

G06F 1216

711114

Method and apparatus are disclosed for identifying and repairing data coherence problems in a storage system including redundant information. The verification and repair process may be initiated during on-line processing. The verification and repair process may proceed during on-line operation.

6484234, Nov 19, 2002

Jun 30, 1998

09/107792

Ishay Kedem - Brookline MA

EMC Corporation - Hopkinton MA

G06F 1200

711113, 711112, 711118, 711135

In one embodiment of the invention, during a single I/O operation, data is destaged from a cache to at least two non-contiguous storage locations of a data storage device without overwriting at least one storage location disposed between the at least two non-contiguous storage locations. In another embodiment, a communication link is established between a controller that controls data flow between a cache and a data storage device, and this communication link is used to destage data from the cache to at least two non-contiguous storage locations of the data storage device without overwriting at least one storage location between the at least two non-contiguous storage locations and without breaking the communication link. In another embodiment of the invention, data is destaged from a cache to a data storage device by transmitting the data to the data storage device, and also transmitting information to the data storage device identifying at least two storage locations to which the data is to be written, and further identifying at least one storage location, disposed between the at least two storage locations, to which the data is not to be written.

6567888, May 20, 2003

Sep 17, 2002

10/245895

Ishay Kedem - Brookline MA

EMC Corporation - Hopkinton MA

G06F 1200

711113, 711135

In one embodiment of the invention, during a single I/O operation, data is destaged from a cache to at least two non-contiguous storage locations of a data storage device without overwriting at least one storage location disposed between the at least two non-contiguous storage locations. In another embodiment, a communication link is established between a controller that controls data flow between a cache and a data storage device, and this communication link is used to destage data from the cache to at least two non-contiguous storage locations of the data storage device without overwriting at least one storage location between the at least two non-contiguous storage locations and without breaking the communication link. In another embodiment of the invention, data is destaged from a cache to a data storage device by transmitting the data to the data storage device, and also transmitting information to the data storage device identifying at least two storage locations to which the data is to be written, and further identifying at least one storage location, disposed between the at least two storage locations, to which the data is not to be written.

6535994, Mar 18, 2003

Jul 5, 2000

09/610405

Ishay Kedem - Brookline MA

EMC Corporation - Hopkinton MA

H02H 305

714 6, 711114

Method and apparatus are disclosed for resolving data coherence problems (or mismatched data caused by a failure to update data) in a storage system that includes redundant information. The data may be stored as CKD records or fixed size blocks. The method and apparatus may identify data coherence problems by comparing fields for which the correct value is known in advance, by comparing fields between more than one copy of corresponding data units and through other disclosed techniques.

6546457, Apr 8, 2003

Sep 29, 2000

09/676709

Arieh Don - Newton MA
Mathieu Gagne - Boston MA
Kenneth Halligan - Leominster MA
Ishay Kedem - Brookline MA
Hana Moreshet - Framingham MA
Alexandr Veprinsky - Brookline MA
Natan Vishlitzky - Brookline MA
Aviram Cohen - Lexington MA

EMC Corporation - Hopkinton MA

G06F 1200

711114, 711165

A method and apparatus for enabling an on-line reconfiguration of striped data in a disk array storage device. A replicated copy of the striped logical device is made in parallel with host operations. A logical device with a new configuration is then substituted for access by the host application even before any data is transferred to locations within the newly configured logical device. Independent processes operating in this disk array storage device reconfigure the data transparently to any host operations while accommodating host I/O requests directed to locations in the new configuration.

6718437, Apr 6, 2004

Mar 27, 2003

10/400208

Arieh Don - Newton MA
Mathieu Gagne - Boston MA
Kenneth Halligan - Leominster MA
Ishay Kedem - Brookline MA
Hana Moreshet - Framingham MA
Alexandr Veprinsky - Brookline MA
Natan Vishlitzky - Brookline MA
Aviram Cohen - Lexington MA

EMC Corporation - Hopkinton MA

G06F 1200

711114, 711165

A method and apparatus for enabling an on-line reconfiguration of striped data in a disk array storage device. A replicated copy of the striped logical device is made in parallel with host operations. A logical device with a new configuration is then substituted for access by the host application even before any data is transferred to locations within the newly configured logical device. Independent processes operating in this disk array storage device reconfigure the data transparently to any host operations while accommodating host I/O requests directed to locations in the new configuration.