Netapp, Inc.

Krishna Murthy Chandraiah Setty Narasingarayanapeta

Rakesh Bhargava M R

Akhil Kaushik

Harsha Handral Sridhara

Preetham Kudgi Shenoy

Rakesh Bhargava Mr

Anoop Chakkalakkal Vijayan

Jose Mathew

Dhruvil Shah

Rakesh Bhargava

Divya Kathiresan

Shrey Sengar

Sisir Shekhar

Omprakash Khandelwal

Nagaraj S Lalsangi

Vijay Srinath

In one embodiment, a method comprises maintaining state information regarding a data synchronous replication status for a storage object of a primary storage cluster and a replicated storage object of a secondary storage cluster. The method includes temporarily disallowing input/output (I/O) operations for the storage object when the storage object of the primary storage cluster has a failure, which causes an internal state as out of sync for the storage object while maintaining an external state as in sync for external entities. The method performs persistent inflight tracking and reconciliation of I/O operations with a first Op log of the primary storage cluster and a second Op log of the secondary storage cluster and performs a resynchronization between the storage object and the replicated storage object based on the persistent inflight tracking and reconciliation of I/O operations.

Usage of Op logs to synchronize across primary and secondary storage clusters of a cross-site distributed storage system and lightweight Op logging

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

In one embodiment, a method comprises maintaining state information regarding a data replication status for a storage object of the storage node of a primary storage cluster with the storage object being replicated to a replicated storage object of a secondary storage cluster, temporarily disallowing input/output (I/O) operations when the storage object has a connection loss or failure. The method further includes initiating a resynchronization between the storage object and the replicated storage object including initiating asynchronous persistent inflight tracking and replay of any missing I/O operations that are missing from one of a first Op log of the primary storage cluster and a second Op log of the secondary storage cluster, and allowing new I/O operations to be handled with the storage object of the primary storage cluster without waiting for completion of the asynchronous persistent inflight tracking and replay at the secondary storage cluster.

Methods and storage nodes to decrease delay in resuming input output (I/O) operations after a non-disruptive event for a storage object of a distributed storage system by utilizing asynchronous inflight replay of the I/O operations

Techniques are provided for replay of metadata and data operations. During initial execution of operations, identifiers of objects modified by the execution of each operation are identified and stored in association with the operations. When the operations are to be replayed (e.g., executed again, such as part of a replication operation or as part of flushing content from a cache to persistent storage), the identifiers are evaluated to determine which operations are independent with respect to one another and which operations are dependent with respect to one another. In this way, independent operations are executed in parallel and dependent operations are executed serially with respect to the operations from the dependent operations depend.

Faster replay of metadata and data operations using inode number based dependency graph

Techniques are provided for selectively allowing or blocking services from utilizing snapshots. A splitter intercepts and assigns timestamps to operations for execution upon files of a file system. If a snapshot is created while there are no pending operation, then the snapshot is tagged to indicate that the snapshot was created while there were no pending operations, and the snapshot is considered a tagged snapshot. Otherwise, the snapshot is not tagged, and is considered an untagged snapshot. Storage services (e.g., backup applications, lifecycle management applications, applications that consider timestamps of files, etc.) are allowed to utilize tagged snapshots and are blocked from utilizes untagged snapshots in order to maintain consistency.

Timestamp consistency for synchronous replication

Systems and methods are described for performing persistent inflight tracking of operations (Ops) within a cross-site storage solution. According to one embodiment, a method comprises maintaining state information regarding a data synchronous replication status for a first storage object of a primary storage cluster and a second storage object of a secondary storage cluster. The method includes performing persistent inflight tracking of I/O operations with a first Op log of the primary storage cluster and a second Op log of the secondary storage cluster, establishing and comparing Op ranges for the first and second Op logs, and determining a relation between the Op range of the first Op log and the Op range of the second Op log to prevent divergence of Ops in the first and second Op logs and to support parallel split of the Ops.

Maintaining the benefit of parallel splitting of ops between primary and secondary storage clusters in synchronous replication while adding support for op logging and early engagement of op logging

Systems and methods are described for performing persistent inflight tracking of operations (Ops) within a cross-site storage solution. According to one embodiment, a method comprises maintaining state information regarding a data synchronous replication status for a first storage object of a primary storage cluster and a second storage object of a secondary storage cluster. The state information facilitates automatic triggering of resynchronization for data replication between the first storage object and the second storage object. The method includes performing persistent inflight tracking of I/O operations with a first Op log of the primary storage cluster and a second Op log of the secondary storage cluster, establishing and comparing Op ranges for the first and second Op logs, and determining a relation between the Op range of the first Op log and the Op range of the second Op log to prevent divergence of Ops in the first and second Op logs and to support parallel split of the Ops.

Techniques are provided for timestamp consistency. An operation targeting a first storage object having a synchronous replication relationship with a second storage object is intercepted. A timestamp is assigned to the operation. A replication operation is created as a replication of the operation. The same timestamp is assigned to the replication operation. The operation is implemented upon the first storage object and the replication operation is implemented upon the second storage object.

Usage of OP logs to synchronize across primary and secondary storage clusters of a cross-site distributed storage system and lightweight OP logging

Techniques are provided for persistent hole reservation. For example, hole reservation flags of operations targeting a first storage object of a first node are replicated into replication operations targeting a second storage object of a second node during a transition operation to transition the first storage object and the second storage object from an asynchronous replication state to a synchronous replication state. In another example, the second storage object is grown to a size of a replication punch hole operation that failed due to targeting a file block number greater than an end of size of the second storage object.

Persistent hole reservation

Techniques are provided for freeing and utilizing unused inodes. For example, an operation, targeting a first storage object of a first node having a replication relationship with a second storage object of a second node, is intercepted. A replication operation is created as a replication of the operation. The operation is implemented upon the first storage object and the replication operation is implemented upon the second storage object. A determination is made that the replication operation uses an inode no longer used by storage objects of the second node. The inode targeted by the replication operation is freed and utilized based upon the inode being a leaf inode. If the inode is a stream directory inode, then data streams of the stream directory inode are moved under a new private inode and the stream directory inode is released.

Growing community of inventors

Bengaluru, India

Krishna Murthy Chandraiah Setty Narasingarayanapeta