Emc IP Holding Company LLC

Emc Corporation

Henry Austin Spang, Iv

Jian Gao

Xinlei Xu

David W Harvey

Changyu Feng

Philippe Armangau

Lifeng Yang

Yousheng Liu

Gregory S Schaffer

David John Agans

Walter A O'Brien, Iii

Ruiyong Jia

Jeffrey Alan Brown

Christopher Alan Seibel

Daniel E Cummins

Peter Puhov

Xiongcheng Li

Robert Foley

Long Zhang

Marc C Cassano

Mark J Cariddi

Peter E Tolvanen

Chris Seibel

Dmitri Prilepski

A method, computer program product, and computing system for receiving one or more IO requests at a cache system for storing content in a storage array. A maximum number of concurrent backend IO requests may be associated with the storage array based upon, at least in part, a change in size of the storage array. The one or more TO requests may be flushed to the storage array via one or more backend IO requests from the cache system based upon, at least in part, the maximum number of concurrent backend IO requests associated with the storage array.

Cache management system and method

A method, computer program product, and computer system for executing one of a reboot and a startup process. A write I/O may be received at a DRAM cache. Data may be written to at least two different NVMe devices. When the data of the write I/O is completely written to the at least two different NVMe devices, a response may be sent to a driver layer.

Integration of NVMe device with DRAM cache system and method

A method of accelerating copy operations is performed by a data storage appliance. The method includes (a) in response to receiving a copy command to copy from a source extent to a target extent, issuing a buffered read command to read from the source extent down a storage stack of the data storage appliance by a driver running on the data storage appliance, the source extent being part of a first logical disk backed by non-volatile storage of the data storage appliance and the target extent being part of a second logical disk backed by non-volatile storage of the data storage appliance, (b) in response to issuing, receiving at the driver an indication from the storage stack that the source extent is empty, and (c) in response to receiving, issuing a zero-fill command to fill the target extent with zeroes down the storage stack by the driver.

Accelerating copy of zero-filled data extents

A data storage system has multi-core processing circuitry and processes data movement requests using a multi-threaded library component having an initial operation of invoking an underlying driver to read data, and subsequent operations of copying data, invoking an underlying driver to write data, and initiating additional data movement operations as necessary to complete data movement for an entire range of the data movement request. Core-affined threads are used to execute library component operations for data movement requests of associated per-core queues. Data movement requests are distributed among the per-core queues for parallel processing of the data movement requests by the respective core-affined threads, and the execution of a core-affined thread includes initially starting the thread on the affined core to perform the initial operation, and subsequently re-starting the thread on the affined core to perform each of the subsequent operations.

Data storage system with core-affined thread processing of data movement requests

A method, computer program product, and computing system for receiving an IO request for a RAID array. An actual queue depth of the RAID array is compared to a maximum queue depth for the RAID array. An IO queue weight is determined for the IO request. The IO queue weight is revised based upon a degrade mode condition for the RAID array, thus defining a revised IO queue weight. The actual queue depth is incremented based upon the revised IO queue weight.

IO request system and method

A method, computer program product, and computing system for determining a queue depth and a flush rate for each of a plurality of pending data queues associated with a cache system, thus defining a queue depth/flush rate pair for each of the plurality of pending data queues. A predicted drain time is determined for each of the plurality of pending data queues based, at least in part, upon the queue depth/flush rate pair, thus defining a plurality of predicted drain times that are respectively associated with the plurality of pending data queues.

A technique for managing storage in a data storage system includes ingesting host data into a data log backed by pages in a cache. The host data are addressed to specified locations in a data object stored in persistent storage devices. When mapping pages in cache to respective target locations in the persistent storage devices, a flag is selectively asserted to indicate whether there is contiguous free space at the target locations. The cache responds to the flag by delaying flushing of flagged pages, which provides more time for the cache to aggregate pages that map to contiguous free space. Meanwhile, pages that are not flagged can be flushed more quickly, enabling the cache to operate efficiently even though flushing of some pages is delayed.

Selectively delaying cache flushing to promote write efficiency

Improved techniques for maintaining cache coherence in a consistent state are provided. These techniques implement a data storage system using a journaled mirrored cache that ensures that storage operations making up certain transactions be performed atomically, so that a system failure does not result in data loss. The improved techniques also allow for efficient communication of mirroring information.

Techniques for maintaining cache coherence by atomically processing groups of storage commands

A method for upgrading storage processors in a storage system includes a first storage processor performing IO requests on a first one or more logical units, and a second storage processor performing IO requests on a second one or more logical units of the plurality of logical units. The method includes causing the first storage processor to stop performing the IO requests on the first one or more logical units and the second storage processor to perform the IO requests on the first one or more logical units. The method includes causing the second storage processor to stop performing the IO requests on the first one or more logical units of the plurality of logical units and a third storage processor to perform the IO requests on the first one or more logical units.

Storage processor hardware upgrade in a storage system

A method, performed at a first storage processor (SP) connected to a mirroring second SP, includes (a) receiving a write command at the first SP from a host directed to a particular address of a data storage array, (b) identifying a reference in a first cache that is uniquely associated with the particular address, the reference having a token count field, (c) determining whether the reference is synchronized with a corresponding reference in a second cache, and (d) if the reference is synchronized with the corresponding reference, then (1) performing a cache write operation on a cache page pointed to by the reference if the reference stores a maximum token count value and (2) otherwise, sending a token request message from the first SP to the second SP over a cache mirroring bus to request a token from the second SP prior to performing the cache write operation.

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Hopkinton, MA, United States of America

Henry Austin Spang, Iv