Emc Corporation

Emc IP Holding Company LLC

Ofer Michael

Alexandr Veprinsky

Michael J Scharland

Qun Fan

Arieh Don

Ian Wigmore

Hui Wang

Patrick Brian Riordan

Stephen Richard Ives

John F Madden, Jr

Hagay Dagan

Roii Raz

Hagit Brit-Artzi

Michael Dudnik

Gabi Hershkovitz

Douglas Eric LeCrone

Mark J Halstead

Haim Kopylovitz

Steven T McClure

John K Walton

Kendell Alan Chilton

Anestis Panidis

Brett D Niver

Gilad Sade

Josef Ezra

Jiahui Wang

Robert DeCrescenzo

Michael Bermingham

James M McGillis

Ronald G Haupert

Dar S Efroni

Clifford Lim

Martin J Feeney

Nadav Popplwell

Leo Cory

Kassem M Abdallah

Described are techniques for processing a data request for a device of a data storage system. A data request directed to a device that is a virtualized device of the data storage system is received. The data storage system has a plurality of devices comprising one or more local devices and one or more virtualized devices. Each of the local devices is a storage device included in the data storage system and each of the virtualized devices is an external storage device with respect to the data storage system and is presented as a local storage device of the data storage system. First processing is performed by a disk adapter in connection with servicing the data request for the device. The first processing includes sending the request to an external storage device corresponding to the virtualized device over a connection in accordance with path information obtained from discovery processing.

Techniques for processing data requests directed to virtualized devices

Described are techniques for performing data migration for a source logical volume and a target. The target is configured as storage for another mirror of the source logical volume prior to copying data from the source logical volume to the target, and if the target is configured storage of another logical volume of the data storage system, the configured storage is remapped as storage for another mirror of the source logical volume prior to copying data from the source logical volume to the target. One or more invalid bits are set indicating that the target does not contain a valid copy of data from the source logical volume. Data is copied from the first mirror of the source logical volume to the target. Invalid bits are cleared as data portions of the first mirror of the source logical volume are copied to the target.

Techniques for performing data migration

Handling a database request includes providing a first database manager on a storage device containing data for the database, generating the database request external to the storage device, providing the database request to the first database manager on the storage device, and the first database manager servicing the database request by obtaining data internally from the storage device and processing the data within the storage device to provide a result thereof, wherein portions of the data that are not part of the result are not provided externally from the storage device. Handling a database request may also include providing a host having a database application running thereon. The database request may be generated by the database application. Handling a database request may also include providing a second database manager on the host, where the second database manager communicates with the first database manager to provide the database request.

Database offload processing

On-line storage devices are migrated to new storage devices in a non-disruptive manner. A host executing multipath I/O software is initially coupled to a source storage device via at least one active path. The target storage device is configured with the source device's device identification information. The target storage device is coupled to the host via a passive path so that the target storage device can return its device identification information to the host but cannot respond to I/O read or I/O write requests from the host. All paths between the host and the source storage device are then disconnected. An on-line data migration session between the source storage device and the target storage device is then activated. The path between the target storage device and the host is then re-configured from passive to active so that the target storage device can respond to I/O read and I/O write requests.

Non-disruptive migration using device identity spoofing and passive/active ORS pull sessions

A system creates a storage area network (SAN) centric storage virtualization layer in front of storage devices. The system allows data mobility and migration without disruption to the one or more host servers attached to the SAN. Specifically, the host servers are not disrupted when switching I/Os between physical and virtual storage, for example, by taking advantage of WWPN spoofing and Fibre Channel VSAN technology. The use of VSANs effectively allow multiple virtual directors and/or switches to be created within a physical director and/or switches, each with their own separate name server, thereby providing complete isolation from one another. The host-storage pathing information is unchanged as the original physical storage port's WWPNs are spoofed by the virtual storage port. The result is two identical WWPNs within the SAN which is normally disallowed; however, by separating the physical port WWPN into one VSAN and the virtual port WWPN into another, the restriction may be circumvented.

Non-disruptive data mobility using virtual storage area networks with split-path virtualization

A partitioned storage subsystem includes a plurality of directors, each having at least one processor thereon, each of the directors acting as one of: a primary director and a secondary director for a subset of logical devices handled by the partitioned storage subsystem, where primary directors actively perform I/O operations for logical devices and wherein secondary directors receive data to mirror memory of a corresponding primary director. The partitioned storage subsystem also includes a global memory distributed among the plurality of directors, where a different portion of the global memory is provided on each of the directors, and includes metadata for the logical devices, provided in the global memory, where the metadata contains information that correlates logical device data with physical device data. The physical device data may be provided by at least one disk drive coupled to at least one of the directors.

Asymetrical device distribution for a partitioned storage subsystem

A storage array includes a plurality of directors, each having at least one processor thereon and a global memory distributed among the plurality of directors. A different portion of the global memory is provided on each of the directors. A interconnect fabric is coupled to each of the directors. Global memory accesses performed by one director to access memory of another director through the interconnect fabric. The storage array also includes a plurality of partitioned storage subsystems, each including a separate subset of the directors, where each of the partitioned storage subsystems handles I/O operations for a plurality of logical devices independently of I/O operations for logical devices of other ones of the partitioned storage subsystems, the I/O operations using metadata provided in the global memory of the corresponding directors and containing information that correlates logical device data with physical device data.

Storage array partitioning

Handling I/O operations for a storage array includes distributing metadata among separate memories of a plurality of directors of the storage array, where the metadata correlates logical device data with physical device data. A first one of the directors receives an I/O operation for a particular logical device. Handling I/O operations may also include determining which of the plurality of directors contains metadata corresponding to the particular logical device, and, in response to the metadata being on a different one of the directors, the first director providing a request to the different one of the directors. The directors may be interconnected by an interconnect fabric. The first one of the directors may provide a request to the second one of the directors via the interconnect fabric. Determining which of the plurality of directors contains metadata correspond to the particular logical device may include using a lookup table.

I/O operations for a storage array

A system for de-duplicating data includes providing a first volume including at least one pointer to a second volume that corresponds to physical storage space, wherein the first volume is a logical volume. A first set of data is detected as a duplicate of a second set of data stored on the second volume at a first data chunk. A pointer of the first volume associated with the first set of data is modified to point to the first data chunk. After modifying the pointer, no additional physical storage space is allocated for the first set of data.

Data de-duplication using thin provisioning

Described are techniques for detecting incompatibilities. A first contents of a data item is determined in accordance with a first set of conventions associated with a first processor architecture. A second contents of said data item is determined in accordance with a second set of conventions associated with a second processor architecture and including at least one convention that is not included in said first set. An actual difference between the first contents and the second contents is determined. It is determined whether the actual difference is expected. If the actual difference is not expected, the data item is flagged as an incompatibility candidate. Code referencing the data item is examined to determine any coding incompatibilities due to coding dependencies.

Techniques for detecting coding incompatibilities

Described are techniques for performing data recovery processing for two failed devices included in a set of devices. It is determined whether the two failed devices are each one of the data devices, a horizontal parity device, or a diagonal parity device. Each of the data devices is partitioned into N&#x2212;1 data segments. The horizontal parity device includes N horizontal parity segments each including parity information for a horizontal grouping of N&#x2212;1 of the data segments. The diagonal parity device includes N diagonal parity segments each including parity information for a diagonal grouping of N&#x2212;1 of the data segments. Recovery processing is performed to recover two failed devices in accordance with the diagonal parity device, the horizontal parity device, and the data devices.

Techniques for fault tolerant data storage

Described are techniques for selective data replication. Cached data is replicated if it is characterized as critical. Critical data may include data associated with a write I/O operation. Cache locations are selected for replicated data so that a first location is mapped to a first memory board and a second location is mapped to a second memory board. Data for a read operation is not replicated in cache. Other non-cache data that is critical and thus replicated includes metadata. Cache locations for data of read and write I/O operations are selected dynamically at the time the I/O operation is made from the same pool of cache locations.

Method, computer readable medium, and data storage system for selective data replication of cached data

A system for displaying logical structure of heterogeneous source code includes a parser configured to read the source code and to generate parsed code. A code mapper having access to the parsed code is configured to generate from that parsed code a map representative of the logical structure of the heterogeneous source code.

Graphical compiler

A system for arbitrating access to a shared resource includes a plurality of microprocessors, a shared resource; and a controller coupled to the plurality of microprocessors and the shared resource by a first bus and a second bus, respectively, the controller including a register having a lock portion associated with each of the plurality of processors and at least one status portion, each of the lock portions indicating whether the associated one of the plurality of microprocessors has obtained access to communicate with the shared resource and each of the at least one status portion includes a bit indicating whether any of the plurality of microprocessors has obtained access to communicate with the shared resource.

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Newton, MA, United States of America

Ofer Michael