Emc Corporation

Other

Daniel Castel

Natan Vishlitzky

Moshe Yanai

Bruno Alterescu

John K Walton

Kendell Alan Chilton

Gadi G Shklarsky

Yuval Ofek

William F Baxter

James Marriott Guyer

Michael Bermingham

Christopher S MacLellan

Brian William Gallagher

Robert A Thibault

Brian D Magnuson

Eli Leshem

Brian K Campbell

Ofer Porat

Lawrence G Pignolet

Gregory S Robidoux

Paul C Wilson

Bruno Altersecu

Mark Botelho

A queuing system wherein at least one input/output (I/O) interface having an outbound queue. A plurality of processing units is coupled to the at least one I/O interface. Each one of the processing units is coupled to a corresponding processing unit memory. Each one of the processing unit memories has an inbound queue for such coupled processing unit. The at least one I/O interface outbound queue stores outbound information being returned to the I/O interface after being processed by one of the processing units. The I/O interface creates queue indices for storage in the inbound queues of the processor unit memories. The I/O interface includes a translation table, such table storing at a location a producer index for the plurality of processing units and a consumer index for such plurality of processing units.

Data system having a virtual queue

A system interface having a plurality of directors, one portion of such directors being adapted for coupling to a host computer/server and another portion of the directors being adapted for coupling to a bank of disk drives. The plurality of directors are interconnected through a network. A common resource section is provided having a resource shared among the plurality of directors. The common shared resource section includes a shared computer code used by the plurality of directors. The code includes computer code for booting up each one of the plurality directors. The common shared code storage section is interconnected to the directors through the network. A second, redundant common shared resource section is provided. The network is a packet switching network.

Data storage system having shared resource

A system having a plurality of printed circuit broads each one having an electrical component thereon. A backplane carries a signal indicative of a performance characteristic of the electrical components on the plurality of printed circuit boards plugged into such backplane. The performance characteristic may be, for example component speed, operating protocol, etc. System start-up is interrupted upon detection of such incompatibility. After start up, upon plugging an additional printed circuit broad having an electrical component thereon with an operating incompatible with the electrical components on the plurality of printed circuit boards into the backplane, the electrical component on such additional printed circuit will not be electrically coupled to the electrical component on the additional printed circuit board from the electrical components of the plurality of printed circuit boards.

System having backplane performance capability selection logic

Two data storage systems are interconnected by a data link for remote mirroring of data. Each volume of data is configured as local, primary in a remotely mirrored volume pair, or secondary in a remotely mirrored volume pair. Normally, a host computer directly accesses either a local or a primary volume, and data written to a primary volume is automatically sent over the link to a corresponding secondary volume. Each remotely mirrored volume pair can operate in a selected synchronization mode including synchronous, semi-synchronous, adaptive copy-remote write pending, and adaptive copy-disk. Direct write access to a secondary volume is denied if a 'sync required' attribute is set for the volume and the volume is not synchronized.

Remote data mirroring

A system interface having: a plurality of front end directors adapted for coupling to a host computer/server; a plurality of back end directors adapted for coupling to a bank of disk drives; a data transfer section having cache memory; a cache memory manager; and, a message network. The cache memory is coupled to the plurality of front end and back end directors. The messaging network operates independently of the data transfer section and is coupled to the plurality of front end and back end. The front end and back end directors control data transfer between the host computer/server and the bank of disk drives in response to messages passing between the front end directors and the back end directors through the messaging network to facilitate data transfer between host computer/server and the bank of disk drives. The data passes through the cache memory in the data transfer section as such data passes between the host computer and the bank of disk drives. The system includes a cache memory manager having therein a memory for storing a map maintaining a relationship between data stored in the cache memory and data stored in the disk drives. The cache memory manager provides an interface between the host computer, the bank of disk drives and the cache memory for determining for the directors whether data to be read from the disk drives, or data to be written to the disk drives, resides in the cache memory. With such an arrangement, the cache memory in the data transfer section is not burdened with the task of transferring the director messaging but rather a messaging network is provided, operative independent of the data transfer section, for such messaging thereby increasing the operating bandwidth of the system interface. Further, the cache memory is no longer burdened with the task of evaluating whether data to be read from the disk drives, or data to be written to the disk drives, resides in the cache memory. The cache memory manager, plurality of front end directors, plurality of back end directors and cache memory are interconnected through a packet switching network.

Data storage system having cache memory manager with packet switching network

A system interface having a backplane adapted to have plugged therein director boards and memory boards. Each one of such director boards includes director board transmit/receive units. Each one of the director board transmit/receive units is associated with a corresponding one of the of memory boards. Each one of the director board transmit/receive units is adapted to be disabled in the absence of the one of the memory boards associated with such one of the director board transmit/receive units. Each one of the memory boards includes memory board transmit/receive units. Each one of the memory board transmit/receive units is associated with a corresponding one of the director boards. Each one of the memory board transmit/receive units is adapted to be disabled to prevent transmit/receive data therethrough in the absence of the one of such director boards associated with such one of the memory board transmit/receive units.

Data storage system having port disable mechanism

Two data storage systems are interconnected by a data link for remote mirroring of data. Each volume of data is configured as local, primary in a remotely mirrored volume pair, or secondary in a remotely mirrored volume pair. Normally, a host computer directly accesses either a local or a primary volume, and data written to a primary volume is automatically sent over the link to a corresponding secondary volume. Each remotely mirrored volume pair can operate in a selected synchronization mode including synchronous, semi-synchronous, adaptive copy&#x2014;remote write pending, and adaptive copy&#x2014;disk. Direct write access to a secondary volume is denied if a 'sync required' attribute is set for the volume and the volume is not synchronized.

A data storage system wherein end-user data is transferred between a host computer and a bank of disk drives through an interface. The interface includes a memory and a directors interconnected through an interface state data bus and end-user data busses. At least one front-end one of the directors is in communication with the host computer and at least one rear-end one of the directors is in communication with the bank of disk drives. The interface state data bus section is in communication with: both the at least one front-end one and the at least one rear-end one of the directors; and to the memory. Each one of the end-user data buses has a first end coupled to a corresponding one of the directors and a second end coupled to the memory. The directors control the end-user data transfer between the host computer and the bank of disk drives through the memory in response to interface state data generated by the directors as such end-user data passes through the end-user data busses. The generated interface state data is transferred among the directors through the memory as such end-user data passes through the end-user bus.

Data storage system

A data storage system wherein end-user data is transferred between a host computer and a bank of disk drives through an interface. The interface includes a memory and a plurality of directors interconnected through an interface state data bus and a plurality of end-user data busses. At least one front-end one of the directors is in communication with the host computer and at least one rear-end one of the directors is in communication with the bank of disk drives. The interface state data bus section is in communication with: both the at least one front-end one and the at least one rear-end one of the directors; and to the memory. Each one of the plurality of end-user data buses has a first end coupled to a corresponding one of the plurality of directors and a second end coupled to the memory. The plurality of directors control the end-user data transfer between the host computer and the bank of disk drives through the memory in response to interface state data generated by the directors as such end-user data passes through the end-user data busses. The generated interface state data is transferred among the directors through the memory as such end-user data passes through the end-user bus.

A method and system for producing a data storage system for transferring data between a host computer/server and a bank of disk drives through a system interface. The system interface has a plurality of first directors, a plurality of second directors, and a global memory. The method includes: providing a backplane having slots adapted to have plugged therein a plurality of printed circuit board. The printed circuit boards include: a plurality of first director boards having the first directors; a plurality of second printed circuit boards having the second directors; a plurality of memory printed circuit boards providing the global memory; a plurality of dummy first director boards having first jumpers; a plurality of dummy second director boards having second jumpers; a plurality of dummy memory boards having third jumpers. The method includes wiring the backplane to effect a connection among the first, second and third jumpers to interconnect the first plurality of director to the host computer/server, the plurality of second plurality of directors to the bank of disk drives and the global memory to the first plurality of directors and to the second plurality of director. The method and system allows the same wired backplane to be used with systems having a different number of memory and director boards and still enable dual-write and redundancy to the global memory.

Data storage system having dummy printed circuit boards with jumpers

Data storage system having dummy printed circuit boards

A data storage system includes data storage and a record locator data structure in random access memory. The record locator data structure includes entries having different lengths. For locating variable-length data records in the data storage, for example, at least some but not all of the entries have a data-length portion indicating data length of a respective data record of the entry when the data length of the respective data record fails to match an expected data length. Each entry, for example, has a fixed length portion including an indication of whether or not the entry has a data-length portion, the fixed length portions are stored sequentially in a first region of address locations of the random access memory, and the data-length portions are stored sequentially in a second region of address locations of the random access memory.

System and method for disk mapping and data retrieval

The invention is directed to techniques for accessing data within a data storage system having a circuit board that includes both a front-end circuit for interfacing with a host and a back-end circuit for interfacing with a storage device. To move data between the host and the storage device, an exchange of data between the front-end circuit and the back-end circuit can occur within the circuit board thus circumventing the cache of the data storage system. Such operation not only reduces traffic through the cache, but also shortens the data transfer latency. In one arrangement, a data storage system includes a cache, a first front-end circuit that operates as an interface between the cache and a first host, a second front-end circuit that operates as an interface between the cache and a second host, a first storage device (e.g., a disk drive, tape drive, CDROM drive, etc.), a second storage device, a first back-end circuit that operates as an interface between the cache and the first storage device, and a second back-end circuit that operates as an interface between the cache and the second storage device. The first front-end circuit and the first back-end circuit reside on a first circuit board. Similarly, the second front-end circuit and the second back-end circuit reside on a second circuit board. Accordingly, data transfer between the first host and the first storage device can occur through the first front-end circuit and the first back-end circuit (both of which are on the first circuit board) and circumvent the cache. Likewise, data transfer between the second host and the second storage device can occur through the second front-end circuit and the second back-end circuit (both of which are on the second circuit board) and circumvent the cache. Such data transfers decreases traffic through the cache and reduces data retrieval latencies for non-cached read operations.

Methods and apparatus for accessing data within a data storage system

Two data storage systems are interconnected by a data link for remote mirroring of data. Each volume of data is configured as local, primary in a remotely mirrored volume pair, or secondary in a remotely mirrored volume pair. Normally, a host computer directly accesses either a local or a primary volume, and data written to a primary volume is automatically sent over the link to a corresponding secondary volume. Each remotely mirrored volume pair can operate in a selected synchronization mode including synchronous, semi-synchronous, adaptive copy-remote write pending, and adaptive copy-disk. Direct write access to a secondary volume is denied if a &ldquo;sync required&rdquo; attribute is set for the volume and the volume is not synchronized. If a &ldquo;volume domino&rdquo; mode is enabled for a remotely mirrored volume pair, access to a volume of the pair is denied when the other volume is inaccessible. In a &ldquo;links domino&rdquo; mode, access to all remotely mirrored volumes is denied when remote mirroring-is disrupted by an all-links failure. The domino modes can be used to initiate application-based recovery, for example, recovering a secondary data file using a secondary log file. In an active migration mode, host processing of a primary volume is concurrent with migration to a secondary volume. In an overwrite cache mode, remote write-pending data in cache can be overwritten. Write data for an entire host channel command word chain is bundled in one link transmission.

Asynchronous remote data mirroring system

An apparatus and method for disk mapping and data retrieval includes a data storage medium on which has been stored a plurality of data records. Each record includes at least a record identification portion, for uniquely identifying each record from among the plurality of data records. The apparatus builds a record locator table in high speed semiconductor memory which comprises the unique record identifiers for the records on the storage medium as well as a record locator index generated by the apparatus, which indicates the address of the data record on the storage medium. Data retrieval is facilitated by first searching the record locator table in high speed semiconductor memory for a requested data record. Utilizing the record locator index associated with the requested data record, the system directly H: accesses the requested data record on the storage medium thereby minimizing storage medium search time. Also disclosed is an apparatus and method for converting CKD formatted data records to FBA formatted disk drives and for building and compressing the &ldquo;count&rdquo; portion of the CKD data formatted record into a record locator table.

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Boston, MA, United States of America

Daniel Castel