Emc Corporation

Emc IP Holding Company LLC

John W Lefferts

Rong Yu

Orit Levin-Michael

Yechiel Yochai

Dan Aharoni

Stephen Richard Ives

Peng Yin

Qun Fan

Pei-Ching Hwang

Marik Marshak

Amnon Naamad

Lee W Sapiro

Roderick Klinger

Described are techniques for processing a data operation in a data storage system. A front-end component of the data storage system receives the data operation. In response to receiving the data operation, the front-end component performs first processing. The first processing includes determining whether the data operation is a read operation requesting to read a data portion which results in a cache miss; and if said determining determines that the data operation is a read operation resulting in a cache miss, performing read miss processing. Read miss processing includes sequential stream recognition processing performed by the front-end component to determine whether the data portion is included in a sequential stream.

Techniques for data prefetching

Storage requirements of one or more applications may be serviced by a mix of different disk technologies across one or more storage tiers. According to the system described herein, desirable or optimal mixes of the different disks may be determined and used in the efficient and cost-effective modification or upgrade of storage arrays. For example, whereas SATA drives may be the most cost effective per gigabyte of storage, some applications may not be able to operate based on SATA performance characteristics. On the other hand, flash drives, which may have high performance characteristics, may be too expensive to be used exclusively in a storage array. The system described herein provides a tool that allows for optimal planning of storage resources in a multi-tier storage environment responsive to workload data of a storage array and based on performance characteristics and costs of the storage resources.

Analysis tool for a multi-tier storage environment

Described are techniques for processing a data operation in a data storage system. A front-end component receives the data operation to read a data portion. In response to receiving the data operation, the front-end component performs first processing. The first processing includes determining whether the data operation is a read operation resulting in a cache hit to a prefetched data portion of a sequential stream, and if said determining determines that said data operation results in a cache hit to a prefetched data portion, performing processing in connection with prefetching additional data for said sequential stream. The processing includes determining whether to prefetch additional data for said sequential stream and, if so, an amount of additional data to prefetch. The processing uses one or more criteria to determine one or more of an amount of data to prefetch in a single prefetch request and a track ahead parameter.

Techniques for determining an amount of data to prefetch

Described are techniques for managing a sequential stream in a data storage system. A front-end component receives a plurality of data operations for a plurality of data portions and determines that the plurality of data portions are associated with a sequential stream. Each of the plurality of data portions of the sequential stream is associated with a sequential stream identifier, and a position indicator uniquely identifying a position of said each data portion in said sequential stream. Each of the plurality of data portions that is prefetched is associated with a remaining prefetched identifier and included in a prefetched chunk of data portions. The front-end component uses information about said sequential stream in connection with managing said sequential stream. The information includes the sequential stream identifier, one or more position indicators, and one or more remaining prefetched identifiers.

Techniques for management of information regarding a sequential stream

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Sutton, MA, United States of America

John W Lefferts