Abstract: A method and apparatus for maintaining file system consistency in a distributed system using version vectors is presented. A method generally includes comparing incarnation and transaction identifiers of a current version vector associated with a file with incarnation and transaction identifiers of a last completed version vector associated with the file. Upon determining that a current version vector reflects operations on the file that are either earlier than or the same as the identifiers in the last completed version vector, the node performing one or more file system operations on the file.

Abstract: A request to write data corresponding to at least a first portion of a file is received. It is determined whether to perform the request either as an in-place write or as an out-of-place write. Performing the in-place write comprises performing a write to a low latency storage device, and performing the out-of-place write comprises performing a write to a higher latency storage device. The request is performed as either the in-place write or the out-of-place write based on the determination. Performing the request as the in-place write includes writing the data to a first location on a storage tier storing the first portion of the file, and performing the request as the out-of-place write includes writing the data to a second location on one of a plurality of storage tiers of a computing node, other than the first location.

Abstract: Disclosed is an improved approach for implementing and maintaining writable snapshots. An efficient approach is provided for implementing snapshots that can be used to immediately create snapshots without incurring any detectable delays in providing access to the new snapshots. Also described are improved metadata structures that can be used to implement and maintain the writable snapshots.

Abstract: Techniques for cloning, writing to, and reading from file system metadata. Cloning involves identifying a first set of pointers included in a first root node in a file system metadata tree structure that stores file system metadata n leaf nodes of the tree structure, creating a first copy of the first root node that includes the first set of pointers, creating a second copy of the first root node that includes the first set of pointers, associating the first copy with a first view, and associating the second copy with a second view. Reading generally involves traversing the tree structure towards a target leaf node that contains data to be read. Writing generally involves traversing the tree structure n the same manner, but also creating copies of any nodes to be modified if those nodes are deemed to have a different treeID than a particular root node.

Abstract: Disclosed is an improved approach to implement I/O and storage device management in a virtualization environment. According to some approaches, a Service VM is employed to control and manage any type of storage device, including directly attached storage in addition to networked and cloud storage. The Service VM implements the Storage Controller logic in the user space, and can be migrated as needed from one node to another. IP-based requests are used to send I/O request to the Service VMs. The Service VM can directly implement storage and I/O optimizations within the direct data access path, without the need for add-on products.

Abstract: Techniques are disclosed which allow a secondary storage system to provide data to non-production workloads in conjunction with performing data backup and protection tasks. As disclosed, a secondary storage system exposes backup data stored by the secondary storage system to other workloads, such as test and development applications, data analytics, etc. These non-production workloads can run at the same time the secondary storage system provides backup services to a primary storage system. This consolidation eliminates the need for an enterprise to deploy separate storage clusters for analytics, test and development applications, etc. and eliminates unnecessary copies of data.

Abstract: According to one embodiment of the present disclosure, a first set of file system objects included in performing a requested file system operation is identified in response to a request to perform a file system operation. An update intent corresponding to the requested file system operation is inserted into a data structure associated with each identified file system object. Each file system object corresponding to the corresponding data structure is modified as specified by the update intent in that data structure. After modifying the file system object corresponding to the corresponding data structure, the update intent is removed from that data structure.

Abstract: Techniques are disclosed for managing a high performance, fault-tolerant, strongly consistent, distributed key-value store system. The key-value store may store information, such as metadata for a distributed file system. Fault-tolerance means that the distributed key-value store continues to provide access to values in the key-value store in spite of a certain number of node failures. To provide this capability, the key-value store may store copies of (key, value) pair on N+1 nodes in order to provide fault tolerance for the failure of up to N nodes. In addition, metadata describing which nodes store a given value is stored on 2N+1 nodes and the distributed key-value store is sized such that there are 3N+1 nodes in a cluster. Doing so allows the key, value store to tolerate a failure of N nodes, while still maintaining a consistent and available key-value store.

Abstract: Disclosed is an improved approach for implementing and maintaining writable snapshots. An efficient approach is provided for implementing snapshots that can be used to immediately create snapshots without incurring any detectable delays in providing access to the new snapshots. Also described are improved metadata structures that can be used to implement and maintain the writable snapshots.

Abstract: Disclosed is an approach for implementing disaster recovery for virtual machines. Consistency groups are implemented for virtual machines, where the consistency group link together two or more VMs. The consistency group includes any set of VMs which need to be managed on a consistent basis in the event of a disaster recovery scenario.

Abstract: Embodiments described herein provide techniques for maintaining consistency in a distributed system (e.g., a distributed secondary storage system). According to one embodiment of the present disclosure, a first set of file system objects included in performing the requested file system operation is identified in response to a request to perform a file system operation. An update intent corresponding to the requested file system operation is inserted into an inode associated with each identified file system object. Each file system object corresponding to the inode is modified as specified by the update intent in that inode. After modifying the file system object corresponding to the inode, the update intent is removed from that inode.

Abstract: Techniques are disclosed for managing a high performance, fault-tolerant, strongly consistent, distributed key-value store system. The key-value store may store information, such as metadata for a distributed file system. Fault-tolerance means that the distributed key-value store continues to provide access to values in the key-value store in spite of a certain number of node failures. To provide this capability, the key-value store may store copies of (key, value) pair on N+1 nodes in order to provide fault tolerance for the failure of up to N nodes. In addition, metadata describing which nodes store a given value is stored on 2N+1 nodes and the distributed key-value store is sized such that there are 3N+1 nodes in a cluster. Doing so allows the key, value store to tolerate a failure of N nodes, while still maintaining a consistent and available key-value store.

Abstract: A request to write data corresponding to at least a first portion of a file is received. It is determined whether to perform the request either as an in-place write or as an out-of-place write. Performing the in-place write comprises performing a write to a low latency storage device, and performing the out-of-place write comprises performing a write to a higher latency storage device. The request is performed as either the in-place write or the out-of-place write based on the determination. Performing the request as the in-place write includes writing the data to a first location on a storage tier storing the first portion of the file, and performing the request as the out-of-place write includes writing the data to a second location on one of a plurality of storage tiers of a computing node, other than the first location.

Abstract: Disclosed is an approach for implementing disaster recovery for virtual machines. Consistency groups are implemented for virtual machines, where the consistency group link together two or more VMs. The consistency group includes any set of VMs which need to be managed on a consistent basis in the event of a disaster recovery scenario.

Abstract: Techniques are disclosed which allow a secondary storage system to provide data to non-production workloads in conjunction with performing data backup and protection tasks. As disclosed, a secondary storage system exposes backup data stored by the secondary storage system to other workloads, such as test and development applications, data analytics, etc. These non-production workloads can run at the same time the secondary storage system provides backup services to a primary storage system. This consolidation eliminates the need for an enterprise to deploy separate storage clusters for analytics, test and development applications, etc. and eliminates unnecessary copies of data.

Abstract: Techniques are disclosed for storing data in a plurality of storage tiers on a computing node. A node receives a request to write data corresponding to at least a first portion of a file. The node determines whether to perform the request either as an in-place write or as an out-of-place write. Upon determining to perform the request as the in-place write, the node writes the data to a first location on a storage tier which currently stores the first portion of the file. Upon determining to perform the request as the out-of-place write, the node writes the data to a second location on one of the storage tiers, other than the first location.

Abstract: A computer implemented method implemented with a processor for assigning a unique identifier for a data item initially deployed at a cluster of a networked environment that includes determining a unique cluster identifier for the cluster of the networked environment, atomically modifying a local counter value at the cluster of the networked environment and appending the unique cluster identifier to the atomically modified local counter value at the cluster of the networked environment to form a unique ID for the data item.

Abstract: Techniques are disclosed which allow a secondary storage system to provide data to non-production workloads in conjunction with performing data backup and protection tasks. As disclosed, a secondary storage system exposes backup data stored by the secondary storage system to other workloads, such as test and development applications, data analytics, etc. These non-production workloads can run at the same time the secondary storage system provides backup services to a primary storage system. This consolidation eliminates the need for an enterprise to deploy separate storage clusters for analytics, test and development applications, etc. and eliminates unnecessary copies of data.

Abstract: A computer implemented method implemented with a processor for assigning a unique identifier for a data item initially deployed at a cluster of a networked environment that includes determining a unique cluster identifier for the cluster of the networked environment, atomically modifying a local counter value at the cluster of the networked environment and appending the unique cluster identifier to the atomically modified local counter value at the cluster of the networked environment to form a unique ID for the data item.

Abstract: Techniques are disclosed which allow a secondary storage system to provide data to non-production workloads in conjunction with performing data backup and protection tasks. As disclosed, a secondary storage system exposes backup data stored by the secondary storage system to other workloads, such as test and development applications, data analytics, etc. These non-production workloads can run at the same time the secondary storage system provides backup services to a primary storage system. This consolidation eliminates the need for an enterprise to deploy separate storage clusters for analytics, test and development applications, etc. and eliminates unnecessary copies of data.