Netapp, Inc.

Lsi Corporation

Avago Technologies General IP (singapore) Pte. Ltd.

Randolph Wesley Sterns

William Patrick Delaney

Charles D Binford

Joseph Moore

Joseph Russell Blount

Keith Moyer

Mark Edward Regester

Kevin Lee Kidney

Reid A Kaufmann

Randy Kay Hall

Yulu Diao

Mohamad H El-Batal

Dennis E Gates

Austino Nicholas Longo

John R Kloeppner

Jeff Stilger

Reid Kaufmann

Chad Schneider

The application relates to writing arbitrarily sized data extents using in-line descriptors, such as headers or footers, into physical blocks to describe the data extents in those physical blocks. Some data extents may be smaller than the size of a physical block, and some data extents may be larger than the size of a physical block. A given physical block therefore includes an in-line descriptor for a data extent in that block, indicating that the data extent starts within that block and also an offset from the beginning of the block to where the data extent starts. The in-line descriptor is included within the block so that when the block is read both the data and the descriptor are read, thereby eliminating performance penalty for reading the descriptor information.

Systems, methods, and computer readable media providing arbitrary sizing of data extents

Systems and methods are described for smoothing-out latency of IO operations processed by a distributed storage system. In some examples, latency is distributed among IO operations to more evenly spread processing of the IO operations over an IO processing interval. A target latency for IO operations for a volume of a distributed storage system is periodically calculated each sample period based on the number of IO operations to be processed during the next IO processing interval for the volume. As IO operations are received for the volume, a latency may be associated with the IO operation based on the target latency and the IO operation may be queued or synchronously processed as appropriate. Responsive to expiration of a time period that is based on at time at which a given IO operation at the head of the queue was received and the assigned latency, the given IO operation is dequeued and processed.

Processing of input/ouput operations by a distributed storage system based on latencies assigned thereto at the time of receipt

A method includes: storing a first data extent on a physical medium, wherein the physical medium is divided into a plurality of storage blocks, wherein each of the storage blocks has a size that is different than a size of the first data extent, further wherein the first data extent is stored to a first block of the plurality of storage blocks; generating a descriptor for the first data extent, wherein the descriptor indicates that the first data extent starts within the first block of the plurality of blocks and indicates an offset from the beginning of the first block at which the first data extent starts; and storing the descriptor within the first block.

A system shares I/O load between controllers in a high availability system. For writes, a controller determines based on one or more factors which controller will flush batches of data from write-back cache to better distribute the I/O burden. The determination occurs after the local storage controller caches the data, mirrors it, and confirms write complete to the host. Once it is determined which storage controller will flush the cache, the flush occurs and the corresponding metadata at a second layer of indirection is updated by that determined storage controller (whether or not it is identified as the owner of the corresponding volume to the host, while the volume owner updates metadata at a first layer of indirection). For a host read, the controller that owns the volume accesses the metadata from whichever controller(s) flushed the data previously and reads the data, regardless of which controller had performed the flush.

Read and write load sharing in a storage array via partitioned ownership of data blocks

A method, a computing device, and a non-transitory machine-readable medium for allocating data compression activities in a storage system are provided. A method includes tracking, by a storage controller, computing resources corresponding to a storage server. The storage controller processes one or more host read requests to access data requested by one or more hosts, the processing of the one or more host read requests including decompressing the data requested by the one or more hosts from the storage server and providing the decompressed data to the one or more hosts. The storage controller determines an amount of available computing resources after processing the one or more host read requests. Based on the amount of available computing resources, the storage controller performs inline compression of a first portion of host write requests and background compression of a second portion of the host write requests.

Systems and methods for allocating data compression activities in a storage system

A system for tracking metadata changes and recovering from system interruptions. With host I/O, corresponding metadata incremental changes are aggregated and stored in a write-ahead log before being performed to their in-memory buffers. As those buffers are flushed, checkpoints are created and stored in the log. As the log wraps to the start, older entries are overwritten after they are freed from any remaining dependencies by newer checkpoints. If metadata entities have not created new checkpoints, they are instructed to in order to free up space for new aggregated batches and checkpoints. After an interruption, the wrap point is located in the log. From the wrap point, the log is scanned backwards to provide checkpoints to metadata entities. The log is then scanned forwards to perform changes specified by aggregated batches. The metadata entities' volatile memory states are recovered to what they were before the interruption.

Write-ahead log maintenance and recovery

A method for mapping a first address space to a second address space is provided. In some embodiments, the method includes creating a first array of lookup entries and one or more second arrays of metadata entries for maintaining an ordering among the lookup entries using a tree structure. Each of the metadata entries includes one or more data index values identifying a corresponding one of the lookup entries by its position in the first array and one or more metadata index values identifying a corresponding one of the metadata entries by its position in one of the one or more second arrays. The method further includes receiving a request including a lookup value, traversing the tree structure to locate a lookup entry corresponding to the lookup value, and when the lookup value is located among the lookup entries, using the located lookup entry to process the request.

Memory efficient lookup structure

Systems and techniques for recovering a storage array are disclosed. These systems and techniques include determining a size corresponding to a storage stripe of the storage array. Pieces assigned to the storage stripe are identified. A storage configuration corresponding to the pieces assigned to the storage stripe is detected. Ordinal information and parity information are determined corresponding to the pieces assigned to the storage stripe. The size determined corresponding to the storage stripe, identification of the pieces assigned to the storage stripe, the storage configuration, the ordinal information, and the parity information is stored in a data store to reconstruct lost or corrupted metadata corresponding to the storage array.

System and method for recovering a storage array

A method includes: communicating input output (I/O) operations between a first storage controller and a storage drive, wherein the storage drive includes a first port and a second port, further wherein the first controller accesses the second port of the storage drive via a second storage controller; measuring bandwidth utilization on a first channel of a plurality of channels between the first storage controller and the storage drive; and in response to measuring the bandwidth utilization, changing a routing scheme for the I/O operations with respect to either the first port or the second port or both.

Dynamic routing of input/output requests in array systems

Systems and methods for improving caching mechanisms in a storage system are disclosed. The method includes storing data associated with a write input/output (I/O) request at a cache; determining an amount of dirty data stored in the cache, where the dirty data is data in the cache that has not yet been written to a persistent storage location managed by a storage system; determining if the amount of dirty data exceeds a threshold value; determining a cache flush rate based on the amount of dirty data stored at the cache, when the amount of dirty data exceeds the threshold value; and writing data from the cache at the determined cache flush rate to the persistent storage location.

Growing community of inventors

Arvada, CO, United States of America

Randolph Wesley Sterns