Emc Corporation

International Business Machines Corporation

Emc IP Holding Company LLC

Eitan Bachmat

Lior Aronovich

Michael Hirsch

Ron Asher

Shmuel Tomi Klein

Haim Bitner

Tao Kai Lam

Ruben Michel

Yuval Ofek

Victoria Dubrovsky

Natan Vishlitzky

Robert S Mason, Jr

Assaf Natanzon

Dan Arnon

Hagit Bachmat

Arieh Don

Alexandr Veprinsky

David W DesRoches

Ron Arnan

Zvi Gabriel Benhanokh

Avinoam Zakai

Moshe Schreiber

Mark Abashkin

Daniel P Leprohon

Jair Moreshet

A computer-implemented method, according to one embodiment includes, for each repository data chunk in repository data that comprises a plurality of the repository data chunks, generating a corresponding set of repository distinguishing characteristics (RDCs). Each set of RDCs is generated by: applying a hash function to the respective input data chunk or repository data chunk to generate a plurality of hashes, each hash comprising a hash value and a hash position within the data chunk, applying a first function to the plurality of generated hashes to identify a first subset of hashes distributed across the data chunk, applying a second function to the hash positions of the hashes of the first subset to identify a second subset of the plurality of generated hashes, and defining the second subset of hashes as the set of RDCs.

Systems and methods for efficient data searching, storage and reduction

Example embodiments of the present invention relate to a method, an apparatus, and a computer program product for mirroring data in a data storage system across a first storage device having a first latency and a second storage device having a second latency. The method includes receiving an I/O at the data storage system and controlling the I/O to the first storage device having the first latency or the second storage device having the second latency according to properties of the I/O and properties of the first storage device having the first latency and the second storage device having the second latency.

Method and apparatus for asymmetric raid

A computer program product for searching a repository of binary uninterpretted data, according to one embodiment, includes a computer readable storage medium having program instructions executable by a computer to cause the computer to perform a method comprising: analyzing, by the computer, segments of each of the repository and input data to determine a repository segment that is similar to an input segment, the analyzing including searching an index of representation values of the repository data for matching representation values of the input in a time independent of a size of the repository and linear in a size of the input data; and analyzing, by the computer, the similar repository segment with respect to the input segment to determine their common data sections while utilizing at least some of the matching representation values for data alignment, in a time linear in a size of the input segment.

A System, Computer Program Product, and Computer-executable method for managing cache de-staging on a data storage system wherein the data storage system provides a Logical Unit (LU), the System, Computer Program Product, and Computer-executable method including dividing the LU into two or more extents, analyzing each of the two or more extents, creating a cache de-staging policy based on the analysis, and managing cache de-staging of the LU based the cache de-staging policy.

Extent level cache destaging

Systems and methods enabling search of a repository for the location of data that is similar to input data, using a defined measure of similarity, in a time that is independent of the size of the repository and linear in a size of the input data, and a space that is proportional to a small fraction of the size of the repository. The similar data segments thus located are further analyzed to determine their common (identical) data sections, regardless of the order and position of the common data sections in the repository and input, and in a time that is linear in the segment size and in constant space.

Systems and methods enabling search of a repository for the location of data that is similar to input data, using a defined measure of similarity, in a time that is independent of the size of the repository and linear in a size of the input data, and a space that is proportional to a small fraction of the size of the repository. Additionally, remote operations are accomplished with significantly reduced system bandwidth by implementing remote differencing operations.

Systems and methods for searching of storage data with reduced bandwidth requirements

A method for providing data indicative of the performance of a competing algorithm and an incumbent algorithm includes evaluating an incumbent-algorithm score indicative of a performance of an incumbent algorithm. The performance of a competing algorithm executing in place of the incumbent algorithm is then simulated. On the basis of the simulation, a competing-algorithm score predictive of a performance of the competing algorithm is evaluated. These scores are then provided to an output device.

Providing data indicative of the performance of a competing algorithm and an incumbent algorithm

A system efficiently determines of the likely effectiveness of the cache memory for various cache memory sizes, based on a prediction of the likely cache miss rate, the prediction being based on operational statistics which are gathered during actual use of the cache memory over one or more time periods, and based on a variety of cache management methodologies. Based on the prediction, the operator or the system can facilitate increasing or decreasing the size of the cache memory, or maintaining the cache memory at its then-current size. The system determines the cache memory's read miss rate from statistics that are collected during use of the cache memory over an arbitrary time interval, including statistics concerning the file information retrieval activity and the extent of activity per unit time for system. Based on the statistics, equations, which are based on the respective cache memory management methodology, including the FIFO (first-in/first-out) methodology or the LRU (least-recently used) methodology, used in managing the cache memory, are solved to generate a prediction of the cache miss rate for a particular cache memory size, which may be larger or smaller than the current cache memory size, and for the particular cache memory management methodology. The system can repeat this a number of times over respective time intervals to determine corresponding predictions based on the cache memory utilization for respective sets of statistics determined during each time interval. Thereafter, the system or an operator can effect a change in the cache memory size based on the cache miss rate predictions.

System and method for assessing the effectiveness of a cache memory or portion thereof using FIFO or LRU using cache utilization statistics

Optimizing performance of physical disk drives in a disk array storage device with a plurality of logical volumes is accomplished by accumulating statistics over an interval to select two logical volumes for an exchange. After testing to determine any adverse effect of making that change, the exchange occurs to more evenly distribute the loading on individual physical disk storage devices. One set of statistics, seek time, is obtained by combining estimated disk access information and an interpolated seek time obtained from a template that stores characteristics seek times among different pairs of segments that define a physical disk device independently of a logical volume configuration.

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Lehavim, Israel

Eitan Bachmat