Emc IP Holding Company LLC

Dell Products Inc.

Dell & Products L.p.

Maher Kachmar

Philippe Armangau

Vamsi K Vankamamidi

Vasudevan Subramanian

Christopher Alan Seibel

Yubing Wang

Michael P Wahl

John F Gillono

James McCoy

Ivan Bassov

Ashok Tamilarasan

Socheavy D Heng

Yining Si

Yaming Kuang

Marshall Hansi Wu

Christopher Jones

Jason C Penney

In at least one embodiment, processing can include: sending, from a host to a data storage system, a first storage reclamation command that identifies a first storage region of physical storage available for reclamation and reuse; in response to the data storage system receiving the first storage reclamation command, sending from the data storage system to the host first feedback information identifying at least a first detected condition on the data storage system; and in response to receiving the first feedback information at the host, the host varying a current rate or frequency of subsequent storage reclamation commands sent to the data storage system based, at least in part, on the first feedback information regarding the first detected condition on the data storage system.

Cooperative adaptive throttling between hosts and data storage systems

A technique for scheduling tasks in a storage system includes predicting excess capacity of processing resources over a known interval of time and determining a quantity of credit based on the predicted capacity. The technique further includes holding back a requested increase in the priority of one or more speed-noncritical tasks by consuming a portion of the credit and thus allowing one or more speed-critical tasks to run with undiminished access to the processing resources.

Credit-based scheduling using load prediction

In at least one embodiment, processing can include: partitioning a first set of CPU cores into a plurality of CPU core subsets each associated with a single corresponding one of a plurality of predefined I/O types; classifying each of a plurality of I/O requests as one of the plurality of predefined I/O types; for each of the plurality of I/O requests, selecting a CPU core from a first CPU core subset of the plurality of CPU core subsets based, at least in part, on the first CPU core subset having a corresponding one of the plurality of predefined I/O types that matches an associated one of the plurality of predefined I/O types of said each I/O request; and processing the plurality of I/O requests on their selected CPU cores.

Techniques for CPU core management based on operation types

A data storage system continually monitors a loading level of processing requests from host computers relative to a predetermined threshold. In response to the loading level not exceeding the predetermined threshold, a first bulk operation request is responded to with a normal acknowledgment issued without a rate-managing delay. In response to the loading level exceeding the predetermined threshold, a third bulk operation request is responded to with a delayed acknowledgment issued with the rate-managing delay and thus delaying issuance by a requesting host of a subsequent fourth bulk operation request to a delayed time after the third bulk operation request. The use of the delayed acknowledgement throttles the rate of bulk operations and thus limits adverse performance impact to other, latency-sensitive operations such as regular read and write operations.

Data storage system employing delayed responses to influence rate of bulk storage operations

A data storage system continually monitors a loading level of processing requests from host computers relative to a predetermined threshold. In response to the loading level not exceeding a predetermined threshold, a first identification request is responded to with a full response identifying all data blocks over a first complete range of a first bulk storage operation. In response to the loading level exceeding the predetermined threshold, a second identification request is responded to with a partial response identifying a subset of data blocks over only a portion of a second complete range of a second bulk storage operation. The partial response causes a host to first process the subset of data blocks and then send an additional identification request for additional blocks of the second complete range, effectively reducing the rate of bulk storage operations and their effect on other, latency-sensitive operations such as reads and writes.

Data storage system employing partial responses to influence rate of bulk storage operations

A method, computer program product, and computing system for allocating a first number of tokens from a plurality of tokens for processing read IO requests from a read IO queue, thus defining a number of allocated read tokens. A second number of tokens may be allocated from the plurality of tokens for processing write IO requests from a write IO queue, thus defining a number of allocated write tokens. It may be determined that the processing of the write IO requests is throttled. In response to determining that the processing of the write IO requests from the write IO queue is throttled, a maximum allowable number of write tokens may be defined. Additional tokens may be allocated for processing the read IO requests from the read IO queue based upon, at least in part, the maximum allowable number of write tokens and the number of allocated write tokens.

System and method for allocating storage system resources during write throttling

A method, computer program product, and computing system for defining a token pool size for a storage system token pool associated with a storage system. An input/output (IO) processing load for the storage system may be determined. The token pool size for the storage system token pool associated with the storage system may be dynamically adjusted based upon, at least in part, one or more changes in the IO processing load determined for the storage system.

System and method for dynamically adjusting priority-based allocation of storage system resources

A method, computer program product, and computer system for receiving an indication about an amount of background IOs a background scheduler is capable of performing on a plurality of applications, wherein the indication may be based upon, at least in part, one of host IO latency and a rate of the host IO latency being at one of a plurality of levels. One or more applications of the plurality of applications on which to perform the background IOs may be determined. The background IO applications to be performed on the one or more applications of the plurality of applications may be scheduled based upon, at least in part, one of the host IO latency and the rate of the host IO latency being at one of the plurality of levels.

System and method for priority orchestration and scheduling of different background operations

A method is provided for use in a storage system to dynamically disable and enable prefetching, comprising: defining a first plurality of time windows; calculating a first plurality of weights; identifying a first plurality of values of a cache metric; calculating a prefetch score for a first type of data based on the first plurality of weights and the first plurality of caching metric values, the prefetch score being calculated by weighing each of the cache metric values based on a respective one of the first plurality of weights that corresponds to a same time window as the cache metric value; and when the prefetch score fails to meet a threshold, stopping prefetching of the first type of data, while continuing to prefetch a second type of data.

Dynamic enabling of metadata prefetch into cache

A technique for storing data in a data storage system detects that a read is being performed pursuant to a data copy request. In response, the data storage system stores a digest of the data being read in an entry of a digest cache. Later, when a write pursuant to the same copy request arrives, the storage system obtains the entry from the digest cache and completes the write request without creating a duplicate copy of the data.

Optimizing inline deduplication during copies

A method of responding to requests to read data from a computerized data storage system is disclosed. The method includes (a) receiving a request to access a set of data stored in an extent of persistent storage of the computerized data storage system, (b) obtaining, from mapping metadata provided for locating the requested extent, a hash digest of the set of data, the hash digest identifying contents of the set of data, (c) indexing into a content-based cache within memory of the computerized data storage system with a key based on the hash digest to locate a cached copy of the set of data within the memory, and (d) returning the cached copy of the set of data from the memory without accessing the extent of data from persistent storage. An apparatus, system, and computer program product for performing a similar method are also provided.

Content-based caching using digests

A method, computer program product, and computer system for receiving, at a computing device, an I/O request directed to a compressed data portion of a file system. A field associated with the compressed data portion may be determined to be invalid. An error may be generated in response to determining that the field associated with the compressed data portion is invalid. The file system may be maintained in an online status while the compressed data portion is invalid.

Growing community of inventors

Marlborough, MA, United States of America

Maher Kachmar