Abstract: Systems, methods, and computer program products for managing a consensus group in a distributed computing cluster, by determining that an instance of an authority module executing on a first node, of a consensus group of nodes in the distributed computing cluster, has failed; and adding, by an instance of the authority module on a second node of the consensus group, a new node to the consensus group to replace the first node. The new node is a node in the computing cluster that was not a member of the consensus group at the time the instance of the authority module executing on the first node is determined to have failed.

Abstract: A method for performing lockless modifications during a rolling upgrade of a column family from an old column family version to a new column family version in a NoSQL database.

Abstract: Disclosed is an improved approach for implementing a storage system having an operation log where data writes are initially performed to a fast operation log, rather than to its permanent storage location. A distributed operation log can be employed to replicate the data to multiple locations in the storage system.

Abstract: A system for managing storage devices, includes a plurality of nodes that implement a virtualization environment, each node of the plurality of nodes comprising a hypervisor, a service virtual machine that sits above the hypervisor, and one or more user virtual machines that sit above the hypervisor; a plurality of storage devices that are accessed by the user virtual machines via the service virtual machines, wherein a first node of the plurality of nodes comprises a first hypervisor, a first service virtual machine and a first set of one or more user virtual machines, wherein a second node of the plurality of nodes comprises a second hypervisor, a second service virtual machine and a second set of one or more user virtual machines, wherein the first hypervisor and the second hypervisor are of different types, and wherein the first virtual machine and the second service virtual machine are of the same type.

Abstract: A system for implementing storage for a virtualization environment, including a plurality of nodes, wherein the plurality of nodes implements a virtualization environment, a plurality of storage devices that are accessed by virtual machines in the virtualization environment, and wherein the plurality of storage devices comprises a local storage device that is locally attached to one of the plurality of nodes, and in which the local storage device can be managed as part of a global storage space for the virtualization environment.

Abstract: A method for performing lockless lookups during a rolling upgrade of a column family from an old column family version to a new column family version in a NoSQL database.

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

Abstract: A method for handling storage in response to migration of a virtual machine in a virtualization environment, including receiving an I/O request for a virtual disk, determining that a service virtual machine which implements a storage controller is not registered as owner of the virtual disk, obtaining ownership of the virtual disk by the service virtual machine, the service virtual machine handling the I/O request after obtaining ownership of the virtual disk.

Abstract: A method for handling storage in response to migration of a virtual machine in a virtualization environment, including receiving an I/O request for a virtual disk, determining that a service virtual machine which implements a storage controller is not registered as owner of the virtual disk, obtaining ownership of the virtual disk by the service virtual machine, the service virtual machine handling the I/O request after obtaining ownership of the virtual disk.

Abstract: Disclosed is an improved approach for implementing a storage system having an operation log where data writes are initially performed to a fast operation log, rather than to its permanent storage location. A distributed operation log can be employed to replicate the data to multiple locations in the storage system.

Abstract: Several methods and a system of a replicated service for write ahead logs are disclosed. In one embodiment, a method includes persisting a state of a distributed system through a write ahead log (WAL) interface. The method also includes maintaining a set of replicas of a WAL through a consensus protocol. In addition, the method includes providing a set of mechanisms for at least one of detection and a recovery from a hardware failure. The method further includes recovering a persistent state of a set of applications. In addition, the method includes maintaining the persistent state across a set of nodes through the hardware failover. In one embodiment, the system may include a WAL interface to persist a state of a distributed system. The system may also include a WAL replication servlet to maintain and/or recover a set of replicas of a WAL.

Abstract: A method for performing lockless lookups during a rolling upgrade of a column family from an old column family version to a new column family version in a NoSQL database.

Abstract: A system for managing de-duplication of data in a virtualization environment, that includes a plurality of nodes, wherein the plurality of nodes implements a virtualization environment, a plurality of primary storage devices that are accessed by virtual machines in the virtualization environment, and wherein data undergoes de-duplication in the virtualization environment such that an instruction to store a data item that is issued by a virtual machine is not duplicatively stored if the data item is already stored in the plurality of the primary storage devices.

Abstract: Disclosed is an approach for overseeing the overall state of a virtual storage system, and for taking actions as necessary to manage the health and efficient performance of that system. A curator entity is provided on a distributed basis to manage and perform these functions. A master curator manages this workload that is performed by multiple slave curators. MapReduce operations are performed to implement the curator workload. Periodically, the master curator coordinates a full scan of all the metadata in the system using three MapReduce operations. Partial scans may also be run using a single MapReduce operation.

Abstract: Disclosed is an improved approach for implementing a storage system having an operation log where data writes are initially performed to a fast operation log, rather than to its permanent storage location. A distributed operation log can be employed to replicate the data to multiple locations in the storage system.

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: 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: 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: Disclosed is an improved approach for using advanced metadata to implement an architecture for managing I/O operations and storage devices for a virtualization environment. According to some embodiments, 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 advanced metadata is used to track data within the storage devices. A lock-free approach is implemented in some embodiments to access and modify the metadata.

Abstract: A method for handling storage in a virtualization environment including identifying a situation in which a storage controller ownership change is to occur for a virtual disk, identifying a candidate replacement owner for the virtual disk and transferring ownership of the virtual disk to the candidate replacement owner.