Netapp, Inc.

Emc Corporation

Akhil Kaushik

Anoop Chakkalakkal Vijayan

Pranab Patnaik

Yuedong Mu

Rithin Kumar Shetty

Krishna Murthy Chandraiah Setty Narasingarayanapeta

Sohan Shetty

Dhruvil Shah

Jian Xing

Ripulkumar Hemantbhai Patel

Rangarajan Suryanarayanan

Andrew Eric Dunn

Vrishali Dattatray Hajare

Omprakash Khandelwal

Subramaniam Periyagaram

Santosh Ananth Rao

Ajay Pratap Singh Kushwah

Devang Kundanlal Shah

Ching-Yuk Paul Ngan

Michael Robin Eisler

Kai Tan

Pashupati Kumar

Murali Subramanian

Srikumar Natarajan

Dipankar Roy

Mayank Joshi

Yogita Bijani

Paul Anthony Powell

Krishnaveni Budati

Arun Kumar Selvam

Balaji Ramani

Nagender Somavarapu

Anil Kumar Ponnapur

Manoj Kumar V Sundararajan

Aravind Srinivasa Raghavan

Shrey Sengar

Gaurav Verma

Ling Zheng

Vikas Yadav

Onkar Bhat

Sharad Jain

Rajesh Desai

Hrishikesh Ashok Tapaswi

Yi Yang

Subramanian Periyagaram

Rakesh Bhargava

Preetham Kudgi Shenoy

Divya Kathiresan

Mukul Verma

Arul Valan

Rohit Chaudhary

Krishna Murthy Chandriah S Narasingarayanapeta

Jian Jack Xing

Jiang Xing

Systems and methods include negotiating a primary bias state for primary and secondary storage sites when a mediator is temporarily unavailable for a multi-site distributed storage system. In one example, a computer-implemented method comprises detecting, with the primary storage site having a primary storage cluster, a temporary loss of connectivity to a mediator or a failure of the mediator. The computer-implemented method includes negotiating the primary bias state and setting the primary bias state on a secondary storage cluster of the secondary storage site when the secondary storage cluster detects a temporary loss of connectivity to the mediator, determining whether the primary storage cluster receives a confirmation of the secondary storage cluster setting the primary bias state, and setting the primary bias state on the primary storage cluster when the primary storage cluster receives the confirmation.

Methods and systems for negotiating a primary bias state in a distributed storage system

Multi-site distributed storage systems and computer-implemented methods are described for improving a resumption time of input/output (I/O) operations during a common snapshot procedure for storage objects. A computer-implemented method includes initiating a snap create handler operation for a storage object of a batch of storage objects having a plurality of replicated datasets with each replicated dataset having a synchronous replication relationship between at least one storage object of the first storage node and at least one replicated storage object of the second storage node, determining whether a consistency point is currently in progress or not, and providing a hint to accelerate a currently in progress consistency point when the consistency point is currently in progress.

Methods and systems for consistency point optimizations for synchronous replicated datasets

Multi-site distributed storage systems and computer-implemented methods are described for improving a resumption time of input/output (I/O) operations during a common snapshot process for storage objects. A computer-implemented method comprises performing a baseline transfer from at least one storage object of a first storage node to at least one replicated storage object of a second storage node, starting the common snapshot process including stop processing of I/O operations, performing a snapshot create operation on the primary storage site for the at least one storage object of the first storage node, resuming processing of I/O operations, and assigning a new universal unique identifier (UUID) to the at least one storage object of the second storage node after resuming processing of I/O operations with the new UUID to identify when file system contents are different than the baseline transfer.

Methods and systems to reduce latency of input/output (I/O) operations based on file system optimizations during creation of common snapshots for synchronous replicated datasets of a primary copy of data at a primary storage system to a mirror copy of the data at a cross-site secondary storage system

Systems and methods are described for efficiently performing various operations at the granularity of a consistency group (CG) within a cross-site storage solution. An example of one of the various operations includes an independent and parallel resynchronization approach that independently brings individual volumes of a CG to a steady state of in-synchronization (InSync), thereby contributing to scalability of CGs by supporting CGs having a large number of member volumes without requiring a change to the resynchronization process. Another example includes preserving dependent write-order consistency when a remote mirror copy goes out-of-synchronization (OOS) for any reason by driving all member volumes OOS responsive to any member volume becoming OOS. Yet another example includes independent creation of snapshots by member volumes to support efficient and on-demand creation by an application of a common snapshots of all or a subset of peered member volumes of a CG with which the application is associated.

Performing various operations at the granularity of a consistency group within a cross-site storage solution

Systems and methods are described for efficiently processing events related to a relationship between a primary copy of data at a primary storage system and a mirror copy of the data at a cross-site secondary storage system of a multi-site distributed storage system. According to an example, a mediator agent that is configured on both primary and secondary storage systems provides coordination and serialization for various events generated in the relationship. The multi-site distributed storage system performs actions based on the event processing such as performing a failover operation from the primary storage system to the secondary storage system or resynchronizing the relationship to ensure application protection and availability.

Methods and systems to interface between a multi-site distributed storage system and an external mediator to efficiently process events related to continuity

One or more techniques and/or computing devices are provided for synchronous replication. For example, synchronous replication relationships are established between a first storage object (e.g., a file, a logical unit number (LUN), a consistency group, etc.), hosted by a first storage controller, and a plurality of replication storage objects hosted by other storage controllers. In this way, a write operation to the first storage object is implemented in parallel upon the first storage object and the replication storage objects in a synchronous manner, such as using a zero-copy operation to reduce overhead otherwise introduced by performing copy operations. Reconciliation is performed in response to a failure so that the first storage object and the replication storage objects comprise consistent data. Failed write operations and replication write operations are retried, while enforcing a single write semantic. Dependent write order consistency is enforced for dependent write operations, such as overlapping write operations.

Synchronous replication

One or more techniques and/or computing devices are provided for managing an arbitrary set of storage items using a granset. For example, a storage controller may host a plurality of storage items and/or logical unit numbers (LUNs). A subset of the storage items are grouped into a consistency group. A granset is created for tracking, managing, and/or providing access to the storage items within the consistency group. For example, the granset comprises application programming interfaces (APIs) and/or properties used to provide certain levels of access to the storage items (e.g., read access, write access, no access), redirect operations to access either data of an active file system or to a snapshot, fence certain operations (e.g., rename and delete operations), and/or other properties that apply to each storage item within the consistency group. Thus, the granset provides a persistent on-disk layout used to manage an arbitrary set of storage items.

Gransets for managing consistency groups of dispersed storage items

Multi-site distributed storage systems and computer-implemented methods are described for improving a resumption time of input/output (I/O) operations during a common snapshot procedure for storage objects. A computer-implemented method includes initiating a snapshot multi create operation to selectively form a batch of first and second synchronous replicated datasets that belong to a first group of storage disks at the primary storage site and corresponding second group of storage disks at the secondary storage site, performing a batch snapshot create operation on the primary storage site by executing snapshots of storage objects on the primary storage site of the batch of first and second synchronous replicated datasets in parallel multiple threads to effectively utilize processing resources on the primary storage site, and initiating an independent workflow and state machine for each storage object of the batch of first and second synchronous replicated datasets.

Methods and systems to reduce latency of input/output (I/O) operations during creation of common snapshots based on batching of synchronous replicated datasets at a primary storage system to a cross-site secondary storage system

One or more techniques and/or computing devices are provided for implementing synchronous replication. For example, a synchronous replication relationship may be established between a first storage controller hosting local storage and a second storage controller hosting remote storage (e.g., replication may be specified at a file, logical unit number (LUN), or any other level of granularity). Data operations and offloaded operations may be implemented in parallel upon the local storage and the remote storage. Error handling operations may be implemented upon the local storage and implement in parallel as a best effort on the remote storage, and a reconciliation may be performed to identify any data divergence from the best effort parallel implementation. Storage area network (SAN) operations may be implemented upon the local storage, and upon local completion may be remotely implemented upon the remote storage.

Synchronous replication for storage

Multi-site distributed storage systems and computer-implemented methods are described for providing common snapshot retention and automatic fanout reconfiguration for an asynchronous leg after a failure event that causes a failover from a primary storage site to a secondary storage site. A computer-implemented method comprises providing an asynchronous replication relationship with an asynchronous update schedule from one or more storage objects of the first storage node to one or more replicated storage objects of the third storage node, creating a snapshot copy of the one or more storage objects of the first storage node, transferring the snapshot copy to the third storage node based on an asynchronous mirror policy, and intercepting the snapshot create operation on the primary storage site and transferring the snapshot copy to the second storage node to provide a common snapshot between the second storage node and the third storage node.

Methods and multi-site systems to provide recovery point objective (RPO) protection, snapshot retention between secondary storage site and tertiary storage site, and automatically initiating realignment and reconfiguration of a protection configuration from the secondary storage site to the tertiary storage site upon primary storage site failure

A computer-implemented method comprises providing a synchronous replication relationship from one or more storage objects of a first storage node to one or more replicated storage objects of a second storage node, providing an asynchronous replication relationship with an asynchronous update schedule from the one or more storage objects of the first storage node to one or more replicated storage objects of the third storage node to provide a protection configuration, tracking, with the third storage node of the tertiary site, a state of the secondary storage site, automatically performing a failover from the primary storage site to the secondary storage site and activating a synchronous mirror copy for the one or more replicated storage objects of the second storage node, and automatically initiating realignment and reconfiguration of the protection configuration to the tertiary storage site based upon the state of the secondary storage site.

Methods and multi-site systems to provide recovery point objective (RPO) protection and automatically initiate realignment and reconfiguration of a protection configuration from the secondary storage site to the tertiary storage site upon primary storage site failure

One or more techniques and/or computing devices are provided for replicating virtual machine disk clones. For example, a first storage controller, hosting first storage, may have a synchronous replication relationship with a second storage controller hosting second storage. A virtual machine, within the first storage, may be specified as having synchronous replication protection. Accordingly, virtual machine disk clones of a virtual machine disk of the virtual machine may be replicated from the first storage to the second storage. For example, virtual machine disk clones may be synchronous replicated, replicated by a resync process invoked by a hypervisor agent, and/or stored and replicated from a clone backup directory.

Cloned virtual machine disk replication

One or more techniques and/or computing devices are provided for resilient replication of storage operations. For example, a first storage controller may host first storage having a replication relationship with second storage hosted by a second storage controller. To improve resiliency against transient network issues of a network between the storage controllers, the first storage controller may implement a queue and retry mechanism to retry replication operations not acknowledge back by the second storage controller within a threshold time. The second storage controller may maintain a cumulative sequence number of a latest replication operation performed in order, an operation response map of replication operations performed out of order, and an operation finder map identifying currently implemented replication operations, which may be used to process incoming replication operations. Single write semantics, write order consistency, and reduction of write amplification may be provided.

Resilient implementation of client file operations and replication

One or more techniques and/or computing devices are provided for resynchronization. For example, a request may be received to create pseudo snapshots of a first consistency group, hosted by a first storage controller, and a second consistency group, hosted by a second storage controller, having a synchronous replication relationship with the first consistency group. Incoming client write requests are logged within an intercept tracking log at the first storage controller. After a first drain without hold of incoming write requests is performed, a first pseudo common snapshot of the second consistency group is created. After a second drain without hold of incoming write operations is performed, a second pseudo common snapshot of the first consistency group and the intercept tracking log is created. The pseudo snapshots and the intercept tracking log (e.g., indicating a delta between the pseudo snapshots) are used to resynchronize the first and second consistency groups.

Low overhead resynchronization snapshot creation and utilization

Systems and methods are provided for bringing a volume of a consistency group (CG) into an in-synchronization (InSync) state while other volumes of the CG remain in the InSync state. According to an example, in order to support recovery from disruptive events in a manner that ensures a zero recovery point objective (RPO) guarantee and insulates an application making use of the CG from adverse impacts, responsive to a triggering event, a Fast Resync process may first be attempted to promptly bring an affected volume back into an in-synchronization (InSync) state from an out of synchronization (OOS) state while allowing other members of the CG to remain in the InSync state. Should the Fast resync process be unsuccessful in bringing the volume back into the InSync state within a predetermined or configurable time threshold, then a second type of resynchronization process may be employed at the CG level.

Resynchronization of individual volumes of a consistency group (CG) within a cross-site storage solution while maintaining synchronization of other volumes of the CG

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Akhil Kaushik