Lsi Logic Corporation

Netapp, Inc.

Lsi Corporation

Symbios, Inc.

International Business Machines Corporation

Symbios Logic Inc.

Donald Roman Humlicek

Rodney A Dekoning

Brian Dennis McKean

Curtis W Rink

Max L Johnson

Theresa Lynn Segura

William Patrick Delaney

Charles E Nichols

Timothy R Snider

Joseph Moore

Wei Sun

Arindam Banerjee

Robin Huber

James Lee Hafner

Douglas William Dewey

Wendy Ann Belluomini

Rodney A DeKoning

Kevin Lee Kidney

Stanley E Krehbiel

Jeffrey A Stilger

Martin Parrish

Gerald James Fredin

William Hetrick

John R Kloeppner

James A Lynn

Kent D Prosch

Robert A DeMoss

Scott Hubbard

Scott Terrill

Dean Lang

John V Sherman

Gregory A Yarnell

Grover G Phillips

Patrick S Flynn

David Ulrich

Gordon Hulpieu

Alan Stewart

Dale L Harris

Greg William Achilles

Christina A Stout

Methods and systems for dynamic hashing in cache sub-systems are provided. The method includes analyzing a plurality of input/output (I/O) requests for determining a pattern indicating if the I/O requests are random or sequential; and using the pattern for dynamically changing a first input to a second input for computing a hash index value by a hashing function that is used to index into a hashing data structure to look up a cache block to cache an I/O request to read or write data, where for random I/O requests, a segment size is the first input to a hashing function to compute a first hash index value and for sequential I/O requests, a stripe size is used as the second input for computing a second hash index value.

Methods and systems for dynamic hashing in caching sub-systems

Systems and techniques for cache management are disclosed that provide improved cache performance by prioritizing particular storage stripes for cache flush operations. The systems and techniques may also leverage features of the storage devices to provide atomicity without the overhead of inter-controller mirroring. In some embodiments, the systems and techniques include a storage controller that stores data in a cache. The data is associated with one or more sectors of a storage stripe that is defined over plurality of storage devices. The storage controller identifies a locality of dirty sectors of the one or more sectors, classifies the storage stripe into a category based on the locality, provides a category ordering of the category relative to at least one other category, and flushes the storage stripe from the cache to the plurality of storage devices according to the category ordering.

Cache flushing and interrupted write handling in storage systems

A method, a computing device, and a non-transitory machine-readable medium for changing ownership of a storage volume from a first controller to a second controller without flushing data, is provided. In the system, the first controller is associated with a first DRAM cache comprising a primary partition that stores data associated with the first controller and a mirror partition that stores data associated with the second controller. The second controller in the system is associated with a second DRAM cache comprising a primary partition that stores data associated with the second controller and the mirror partition associated with the first controller. Further, the mirror partition in the second DRAM cache stores a copy of a data in the primary partition of the first DRAM cache and the mirror partition in the first DRAM cache stores a copy of a data in the primary partition of the second DRAM cache.

Changing storage volume ownership using cache memory

Method and systems for a storage system are provided. Simulated cache blocks of a cache system are tracked using cache metadata while performing a workload having a plurality of storage operations. The cache metadata is segmented, each segment corresponding to a cache size. Predictive statistics are determined for each cache size using a corresponding segment of the cache metadata. The predictive statistics are used to determine an amount of data that is written for each cache size within certain duration. The process then determines if each cache size provides an endurance level after executing a certain number of write operations, where the endurance level indicates a desired life-cycle for each cache size.

Methods and systems for using predictive cache statistics in a storage system

Methods and systems for managing caching mechanisms in storage systems are provided where a global cache management function manages multiple independent cache pools and a global cache pool. As an example, the method includes: splitting a cache storage into a plurality of independently operating cache pools, each cache pool comprising storage space for storing a plurality of cache blocks for storing data related to an input/output ('I/O') request and metadata associated with each cache pool; receiving the I/O request for writing a data; operating a hash function on the I/O request to assign the I/O request to one of the plurality of cache pools; and writing the data of the I/O request to one or more of the cache blocks associated with the assigned cache pool. In an aspect, this allows efficient I/O processing across multiple processors simultaneously.

Methods and systems for cache management in storage systems

A system and method of transposed storage in RAID arrays includes a storage manager with an interface for receiving storage requests associated with multi-segment blocks stored in a storage array, a controller for processing the received storage requests and controlling the storage manager, and a write request handler. The storage array includes a plurality of storage devices for which consecutive logical addresses are assigned to different ones of the storage devices. The write request handler is configured to process block write requests and send segment write requests to the storage array based on the write requests so that each segment of a given multi-segment block is written to a single respective one of the storage devices in the storage array. In some embodiments, the storage manager further includes a read request handler configured to determine logical addresses of requested segments and send segment read requests to the storage array.

System and method for transposed storage in RAID arrays

A system and method for maintaining operation of a storage array with one or more failed storage devices and for quickly recovering when failing devices are replaced are provided. In some embodiments, the method includes receiving a data transaction directed to a volume and determining that a storage device associated with the volume is inoperable. In response to determining that the storage device is inoperable, a data extent is recorded in a change log in a storage controller cache. The data extent is associated with the data transaction and allocated to the storage device that is inoperable. The data transaction is performed using at least one other storage device associated with the volume, and data allocated to the storage device is subsequently reconstructed using the recorded data extent.

Data tracking for efficient recovery of a storage array

System and method for transposed storage in raid arrays

Technology is disclosed for performing background initialization on protection information enabled storage volumes or drives. In some embodiments, a storage controller generates multiple I/O requests for stripe segments of each drive (e.g., disk) of multiple drives of a RAID-based system (e.g., RAID-based disk array). The I/O requests are then sorted for each of the drives according to a pre-determined arrangement and initiated in parallel to the disks while enforcing the pre-determined arrangement. Sorting and issuing the I/O requests in the manner described herein can, for example, reduce drive head movement resulting in faster storage subsystem initialization.

Background initialization for protection information enabled storage volumes

Atomic write operations for storage devices are implemented by maintaining the data that would be overwritten in the cache until the write operation completes. After the write operation completes, including generating any related metadata, a checkpoint is created. After the checkpoint is created, the old data is discarded and the new data becomes the current data for the affected storage locations. If an interruption occurs prior to the creation of the checkpoint, the old data is recovered and any new is discarded. If an interruption occurs after the creation of the checkpoint, any remaining old data is discarded and the new data becomes the current data. Write logs that indicate the locations affected by in progress write operation are used in some implementations. If neither all of the new data nor all of the old data is recoverable, a predetermined pattern can be written into the affected locations.

Atomic write operations for storage devices

A method for managing data movement in a multi-level cache system includes selecting at least one outgoing data block from a primary cache when an unallocated space of the primary cache has reached a minimum threshold, initiating a de-stage process for de-staging the outgoing data block, and terminating the de-stage process when the unallocated space has reached an upper threshold. The de-stage process includes storing the outgoing data block in a secondary cache when a cache hit has occurred before. The cache hit may be an actual cache hit or a 'ghost' cache hit wherein only metadata is stored in the secondary cache. A method for de-staging an outgoing data block from a higher level cache which includes storing an outgoing data block in a lower level cache when a cache hit rate satisfies a predetermined condition and storing metadata in the lower level cache is also disclosed.

Methods for managing data movement and destaging data in a multi-level cache system utilizing threshold values and metadata

Methods and systems for migrating data between storage tiers may include various operations, including, but not limited to: determining at least one activity index of at least one data storage region; receiving an input/output request addressing at least one data segment included in the at least one data storage region; qualifying a data segment addressed by the input/output request for migration to at least one higher-performing storage device; and adding a data segment reference associated with a qualified data segment to a priority queue according to the at least one activity index.

Methods and systems for migrating data between storage tiers

Methods and structure for automated determination and reconfiguration of the size of a cache memory in a storage system. Features and aspects hereof generate historical information regarding frequency of hits on cache lines in the cache memory. The history maintained is then analyzed to determine a desired cache memory size. The historical information regarding cache memory usage may be communicated to a user who may then direct the storage system to reconfigure its cache memory to a desired cache memory size. In other embodiments, the storage system may automatically determine the desired cache memory size and reconfigure its cache memory. The method may be performed automatically periodically, and/or in response to a user's request, and/or in response to detecting thrashing caused by least recently used (LRU) cache replacement algorithms in the storage system.

Methods and structure for determining cache size in a storage system

methods and systems for monitoring data activity may include various operations, including, but not limited to: modifying a value of at least one counter in response to one or more input/output requests directed to at least one data storage region during a first time interval; storing a first cumulative value of the counter modified in response to one or more input/output requests directed to at least one data storage region during the first time interval following the expiration of the first time interval; modifying a value of at least one counter in response to one or more requests directed to the at least one data storage region during a second time interval; storing a second cumulative value of the counter modified in response to one or more requests directed to the at least one data storage region during the second time interval following the expiration of the second time interval; and computing at least one activity index for the at least one data storage region from at least the first cumulative value and the second cumulative value.

Methods and systems for tracking data activity levels

Growing community of inventors

Wichita, KS, United States of America

Donald Roman Humlicek