Netapp, Inc.

Oath Inc.

Network Appliance, Inc.

Ananthan Subramanian

Ram Kesavan

Matthew Fontaine Curtis-Maury

Vinay Devadas

Kevin Daniel Varghese

Anil Paul Thoppil

Cheryl Marie Thompson

Abdul Basit

Qinghua Zheng

Parag Sarfare

Ganga Bhavani Kondapalli

Ravikanth Dronamraju

Arindam Banerjee

Daniel David McCarthy

Sriram Venketaraman

Asif Imtiyaz Pathan

Santhosh Selvaraj

Mark Smith

Sandeep Yadav

Szu-Wen Kuo

Christopher Cason

Nikhil Mattankot

Mohit Gupta

Rajesh Khandelwal

Subramaniam Periyagaram

Yong Cho

Manan Dahyabhai Patel

Hristo Bojinov

Joshua Oren Silberman

Sunitha Sunil Sankar

Blake H Lewis

Ashish Prakash

Rohit Shankar Singh

Rickard Edward Faith

Joseph Brown

Richard Parvin Jernigan, Iv

Tijin George

Dnyaneshwar Nagorao Pawar

Srishylam Simharajan

Wesley R Witte

Venkateswarlu Tella

Tianyu Jiang

Lawrence Wen-Hao Chang

Robert Jan Sussland

Rupa Natarajan

Suhas Urkude

Hiroshi Ishii

Nikul Y Patel

Yash Hetal Trivedi

Kumaran Nagappan

Vikhyath Rao

Bulli Venkata Rajesh Vipperla

Sridevi Jantli

Manish Katiyar

Bharadwaj Vellore Ramesh

Meera Odugoudar

Raymond Jordan Go

Sanjay Subramanian Seshadri

Rahul Thapliyal

Kartik Rathnakar

Rimas Svarcas

Christopher Clark Corey

Garima Choudhary

John Frederick Destefano

Zi-Bin Yang

Girish Hebbale Venkatasubbaiah

Jawahar Tadipatri

Bipin Tomar

William Arthur Gutknecht

Vijayabhaskar Rao Sirigineni

Vetrivelan Kaliyaperumal

Joseph Allen Brown, Jr

Swaroop Vikram Choudhari

Chad Edmund Schneider

Daniel Mccarthy

Aziz Gulbeden

Travis Ryan Grusecki

Christian Compton

Fumiaki Okushi

Lawrence Chang

Techniques are provided for forwarding operations to bypass persistent memory. A modify operation, targeting an object, may be received at a persistent memory tier of a node. If a forwarding policy indicates that forwarding is not enabled for the modify operation and the target object, then the modify operation is executed through a persistent memory file system. If the forwarding policy indicates that forwarding is enabled for the modify operation and the target object, then the modify operation is forwarded to a file system tier as a forwarded operation for execution through a storage file system.

Forwarding operations to bypass persistent memory

Techniques are provided for providing a storage abstraction layer for a composite aggregate architecture. A storage abstraction layer is utilized as an indirection layer between a file system and a storage environment. The storage abstraction layer obtains characteristic of a plurality of storage providers that provide access to heterogeneous types of storage of the storage environment (e.g., solid state storage, high availability storage, object storage, hard disk drive storage, etc.). The storage abstraction layer generates storage bins to manage storage of each storage provider. The storage abstraction layer generates a storage aggregate from the heterogeneous types of storage as a single storage container. The storage aggregate is exposed to the file system as the single storage container that abstracts away from the file system the management and physical storage details of data of the storage aggregate.

Composite aggregate architecture

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 repairing a primary slice file, affected by a storage device error, by using one or more dead replica slice files. The primary slice file is used by a node of a distributed storage architecture as an indirection layer between storage containers (e.g., a volume or LUN) and physical storage where data is physically stored. To improve resiliency of the distributed storage architecture, changes to the primary slice file are replicated to replica slice files hosted by other nodes. If a replica slice file falls out of sync with the primary slice file, then the replica slice file is considered dead (out of sync) and could potentially comprise stale data. If a storage device error affects blocks storing data of the primary slice file, then the techniques provided herein can repair the primary slice file using non-stale data from one or more dead replica slice files.

Slice file recovery using dead replica slice files

Techniques are provided for data management across a persistent memory tier and a file system tier. A block within a persistent memory tier of a node is determined to have up-to-date data compared to a corresponding block within a file system tier of the node. The corresponding block may be marked as a dirty block within the file system tier. Location information of a location of the block within the persistent memory tier is encoded into a container associated with the corresponding block. In response to receiving a read operation, the location information is obtained from the container. The up-to-date data is retrieved from the block within the persistent memory tier using the location information for processing the read operation.

Data management across a persistent memory tier and a file system tier

In various examples, data storage is managed using a distributed storage management system that is resilient. Data blocks of a logical block device may be distributed across multiple nodes in a cluster. The logical block device may correspond to a file system volume associated with a file system instance deployed on a selected node within a distributed block layer of a distributed file system. Each data block may have a location in the cluster identified by a block identifier associated with each data block. Each data block may be replicated on at least one other node in the cluster. A metadata object corresponding to a logical block device that maps to the file system volume may be replicated on at least another node in the cluster. Each data block and the metadata object may be hosted on virtualized storage that is protected using redundant array independent disks (RAID).

Distributed file system that provides scalability and resiliency

Techniques are provided for journal replay optimization. A distributed storage architecture can implement a journal within memory for logging write operations into log records. Latency of executing the write operations is improved because the write operations can be responded back to clients as complete once logged within the journal without having to store the data to higher latency disk storage. If there is a failure, then a replay process is performed to replay the write operations logged within the journal in order to bring a file system up-to-date. The time to complete the replay of the write operations is significantly reduced by caching metadata (e.g., indirect blocks, checksums, buftree identifiers, file block numbers, and consistency point counts) directly into log records. Replay can quickly access this metadata for replaying the write operations because the metadata does not need to be retrieved from the higher latency disk storage into memory.

Journal replay optimization

Techniques are provided for key-value store and file system integration to optimize key value store operations. A key-value store is integrated within a file system of a node. A log structured merge tree of the key-value store may be populated with a key corresponding to a content hash of a value data item stored separate from the key. A random distribution search may be performed upon a sorted log of the log structured merge tree to identify the key for accessing the value data item. A starting location for the random distribution search is derived from key information, a log size of the sorted log, and/or a keyspace size of a keyspace associated with the key.

Key-value store and file system integration

Techniques are provided for maintaining and recomputing reference counts in a persistent memory file system of a node. Primary reference counts are maintained for pages within persistent memory of the node. In response to receiving a first operation to link a page into a persistent memory file system of the persistent memory, a primary reference count of the page is incremented before linking the page into the persistent memory file system. In response to receiving a second operation to unlink the page from the persistent memory file system, the page is unlinked from the persistent memory file system before the primary reference count is decremented. Upon the node recovering from a crash, the persistent memory file system is traversed in order to update shadow reference counts for the pages with correct reference count values, which are used to overwrite the primary reference counts with the correct reference count values.

Maintaining and recomputing reference counts in a persistent memory file system

Techniques are provided for utilizing a log to free pages from persistent memory. A log is maintained to comprise a list of page block numbers of pages within persistent memory of a node to free. A page block number, of a page, within the log is identified for processing. A reference count, corresponding to a number of references to the page block number, is identified. In response to the reference count being greater than 1, the reference count is decremented and the page block number is removed from the log. In response to the reference count being 1, the page is freed from the persistent memory and the page block number is removed from the log.

Freeing pages within persistent memory

Methods and systems for co-locating journaling and data storage are provided. Separate journal and volume partitions may be maintained within each logical storage unit (e.g., Logical Unit Number (LUN)) of a distributed storage system. Journaling of metadata associated with write requests received from one or more clients may be distributed by identifying a destination logical storage unit to which data associated with a given write request is to be stored and causing the data and metadata to be persisted to disk by journaling the metadata and the data to respective portions of an active log within the journal partition of the destination logical storage unit. By using the same logical storage unit for both journaling of write requests and writing the data associated with such write requests, the bottleneck due to there being only a single device or storage unit handling all metadata for all write requests can be avoided.

Co-located journaling and data storage for write requests

Failover methods and systems for a networked storage environment are provided. In one aspect, a read request associated with a first storage object is received, during a replay of entries of a log stored in a non-volatile memory of a second storage node for a failover operation initiated in response to a failure at a first storage node. The second storage node operates as a partner node of the first storage node. The read request is processed using a filtering data structure that is generated from the log prior to the replay and identifies each log entry. The read request is processed when the log does not have an entry associated with the read request, and when the filtering data structure includes an entry associated with the read request, the requested data is located at the non-volatile memory.

Network storage failover systems and associated methods

Techniques are provided for implementing a persistent memory storage tier to manage persistent memory of a node. The persistent memory is managed by the persistent memory storage tier at a higher level within a storage operating system storage stack than a level at which a storage file system of the node is managed. The persistent memory storage tier intercepts an operation targeting the storage file system. The persistent memory storage tier retargets the operation from targeting the storage file system to targeting the persistent memory. The operation is transmitted to the persistent memory.

Persistent memory architecture

Systems and methods for performing a zero-copy volume move between nodes of a distributed storage system are provided. In one example, an approach for performing a zero-copy volume move is proposed in which volume data may be maintained in place within a storage pod and need not be copied to move a given volume between the source node and the destination node. In one embodiment, metadata (e.g., a top-most physical volume block number (PVBN) of a node tree representing the volume at issue) of a write-anywhere file system is copied from the source node to the destination node. Since the storage pod is associated with a global PVBN space that is visible and accessible to all nodes of the distributed storage system, as a result of copying the top-mode PVBN of the volume to the destination node, anything below the top-most PVBN will automatically be visible to the destination node.

Zero-copy volume move within a distributed storage system

Techniques are provided for coordinating snapshot operations across multiple file systems. A notification may be received that a snapshot of data stored across a persistent memory file system and a storage file system is to be generated. Forwarding, of modify operations from a persistent memory tier to a file system tier for execution through the storage file system, may be enabled. Framing may be initiated to notify the storage file system of blocks within the persistent memory file system that comprise more up-to-date data than corresponding blocks within the storage file system. In response to the framing completing, a consistency point operation is performed to create the snapshot and to create a snapshot image as part of the snapshot.

Coordinating snapshot operations across multiple file systems

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San Ramon, CA, United States of America

Ananthan Subramanian