Netapp, Inc.

Abdul Basit

Ananthan Subramanian

Ram Kesavan

Matthew Fontaine Curtis-Maury

Vinay Devadas

Mark Smith

Daniel David McCarthy

Yash Hetal Trivedi

Rohit Shankar Singh

Christopher Cason

Joseph Brown

Hiroshi Ishii

Jian Hu

Curtis E Hrischuk

Kevin Daniel Varghese

Kevin Faulkner

Leon Fairbanks

Siu Wu

Christopher Clark Corey

Vinod Vasant Pai

Phil Larson

William Arthur Gutknecht

Swaroop Vikram Choudhari

Chad Edmund Schneider

Techniques are provided for block allocation for persistent memory during aggregate transition. In a high availability pair including first and second nodes, the first node makes a determination that control of a first aggregate is to transition from the first node to the second node. A portion of available free storage space is allocated from a first persistent memory of the first node as allocated pages within the first persistent memory. Metadata information for the allocated pages is updated with an identifier of the first aggregate to create updated metadata information reserving the allocated pages for the first aggregate. The updated metadata information is mirrored to the second node, so that the second node also reserves those pages. Control of the first aggregate is transitioned to the second node. As a result, the nodes do not attempt allocating the same free pages to different aggregates during a transition.

Block allocation for persistent memory during aggregate transition

Techniques are provided for failing over an aggregate from one file system instance to a different file system instance of a distributed scale-out storage system. The aggregate may be stored within distributed storage that is accessible to a plurality of file system instances of the distributed scale-out storage system. When the aggregate is failed over from a first file system instance to a second file system instance, the first file system instance may still have a valid read lease that allows the first file system instance to serve client I/O, directed to the aggregate, using a cache. In order to prevent the first file system instance from serving stale data from the cache before the read lease expires, state machines and a set of control data are used to ensure that the second file system instance attaches to the aggregate only after the read lease has expired.

Aggregate failover for a distributed scale-out storage system

Techniques are provided for implementing write ordering for persistent memory. A set of actions are identified for commitment to persistent memory of a node for executing an operation upon the persistent memory. An episode is created to comprise a first subset of actions of the set of actions that can be committed to the persistent memory in any order with respect to one another such that a consistent state of the persistent memory can be reconstructed in the event of a crash of the node during execution of the operation. The first subset of actions within the episode are committed to the persistent memory and further execution of the operation is blocked until the episode completes.

Write ordering for persistent memory

Techniques are provided for dynamically implementing quality of service policies for a distributed storage system based upon resources saturation. A quality of service policy is defined for throttling I/O operations received by a node of the distributed storage system based upon whether resources of the node have become saturated. The quality of service policy is dynamically implemented based upon ever changing resource utilization and saturation. Dynamically implementing the quality of service policy improves the ability to efficiently utilize resources of the node compared to conventional static polices that cannot adequately react to such changing considerations and resource utilization/saturation. With conventional static policies, an administrator manually defines a minimum amount of guaranteed resources and/or a maximum resource usage cap that could be set to values that result in inefficient operation and resource starvation. Dynamically implementing the quality of service policy results in more efficient operation and mitigates resource starvation.

Dynamic quality of service implementation based upon resource saturation

Techniques are provided for dynamically implementing quality of service policies using a configurable quality of service provider pipeline. A quality of service policy is defined for throttling I/O operations received by a node based upon whether resources of the node have become over utilized. The quality of service policy is used to dynamically construct a quality of service provider pipeline with select quality of service providers that improve the ability to efficiently utilize resources compared to conventional static polices that cannot adequately react to changing considerations and resource utilization/saturation. With conventional static policies, an administrator manually defines a minimum amount of guaranteed resources and/or a maximum resource usage cap that could be set to values that result in inefficient operation and resource starvation. Dynamically constructing and utilizing the quality of service provider pipeline results in more efficient operation and mitigates resource starvation.

Configurable quality of service provider pipeline

Techniques are provided for compacting indirect blocks. For example, an object is represented as a structure including data blocks within which data of the object is stored and indirect blocks including block numbers of where the data blocks are located in storage. Block numbers within a set of indirect blocks are compacted into a compacted indirect block including a base block number, a count of additional block numbers after the base block number in the compacted indirect block, and a pattern of the block numbers in the compacted indirect block. The compacted indirect block is stored into memory for processing access operations to the object. Storing compacted indirect blocks into memory allows for more block numbers to be stored within memory.

File system format for persistent memory

Techniques are provided for persistent memory file system reconciliation. As part of the persistent memory file system reconciliation, high level file system metadata associated with a persistent memory file system of persistent memory is reconciled. Client access to the persistent memory file system is inaccessible until reconciliation of the high level file system metadata has completed. A first scanner is executed to traverse pages of the persistent memory in order to fix local inconsistencies associated with the pages. A local inconsistency of a first set of metadata or data of a page is fixed using a second set of metadata or data of the page. The first scanner is executed asynchronously in parallel with processing client I/O directed to the persistent memory file system.

Persistent memory file system reconciliation

Techniques are provided for implementing a file system format for persistent memory. A node, with persistent memory, receives an operation associated with a file identifier and file system instance information. A list of file system info objects are evaluated to identify a file system info object matching the file system instance information. An inofile, identified by the file system info object as being associated with inodes of files within an instance of the file system targeted by the operation, is traversed to identify an inode matching the file identifier. If the inode has an indicator that the file is tiered into the persistent memory, then the inode it utilized to facilitate execution of the operation upon the persistent memory. Otherwise, the operation is routed to a storage file system tier for execution by a storage file system upon storage associated with the node.

Methods, non-transitory computer readable media, and computing devices that execute a storage operation, without journaling the storage operation in a log, and withhold from a file system a list of freed inodes including an indication of an inode freed as a result of the execution of the storage operation. A consistency point operation is then initiated that retrieves storage operations logged as journal entries in the log and commits a result of each of the storage operations to data storage devices. A list of available inodes is updated based on the list of freed inodes, when the consistency point operation is determined to be complete. This technology reduces the number of storage operations that are required to be journaled to maintain consistency of a file system, thereby reducing the runtime resources required to facilitate the journaling and replay resource required to replay the storage operations following a recovery.

Growing community of inventors

Morrisville, NC, United States of America

Abdul Basit