Microsoft Technology Licensing, LLC

Vyacheslav Kuznetsov

Andrea D'Amato

David Allen Dion

Vladimir Petter

Vinod R Shankar

Karan Mehra

Alan M Warwick

Parveen Kumar Patel

Roopesh C Battepati

Shiv Kumar Rajpal

Marios Zikos

Ganesh Prasad

Volodymyr Ivanov

Sarosh Cyrus Havewala

Darren Glen Moss

Rajeev Y Nagar

Sai Sudhir Anantha Padmanaban

Ankur Kasturiya

Henry Aloysius

Gregory Robert Domzalski

Systems and methods for live migration of VMs between different nodes are provided. The system and methods utilize a heat map and an access pattern to determine the fetching order of files and/or blocks from the cache of a host node for rebuilding the cache on a destination node. The systems and methods are able to persist the cache of a host node across a crash, allowing a destination node to fetch blocks and/or files from the cache on the host node after a crash instead of having to access the VM files and/or blocks from an original source. Accordingly, the systems and methods decrease migration latency of the VM and free up network bandwidth during the live migration when compared to prior systems and methods that utilize just the heat map to determine the fetching order and/or that are not able to persist the cache across a crash.

Systems and methods for live migration of a virtual machine based on heat map and access pattern

Disclosed herein is a system and method for automatically moving an application from one site to another site in the event of a disaster. Prior to coming back online the application is configured with information to allow it to run on the new site without having to perform the configuration actions after the application has come online. This enables a seamless experience to the user of the application while also reducing the associated downtime for the application.

Application transparent continuous availability using synchronous replication across data stores in a failover cluster

Embodiments provide a method and system for enabling access to a storage device. Specifically, a node may request admittance to a cluster that has read and write access to a storage device. The node seeking access to the storage device must be first be approved by other nodes in the cluster. As part of the request, the node seeking access to the storage device sends a registration key to a storage device. Upon expiration of a registration timer, the node seeking access to the storage device receives a registration table from the storage device and determines whether its registration key is stored in the registration table. If the registration key is stored in the registration table the node has been accepted in the cluster and as a result, has been granted read and write access to the storage device.

Controlling storage access by clustered nodes

Recovery requests are scheduled and prioritized according to priority valuations of the minimum time to next failure relative to the minimum time to next recovery for corresponding storage data sets. The prioritization can be performed by an upper layer recovery scheduler that dispatches requests to different storage units and/or by lower layers and individual storage unit schedulers. Prioritizations can be reflected in tagging on recovery requests, as determined by a first entity, and/or determined dynamically at the point of dispatch and processing.

System reliability by prioritizing recovery of objects

A cluster based file service may operate on a cluster of two or more independent devices that have access to a common data storage. The file service may have a namespace definition with each device in the cluster, but may be modified by any device operating the file service. Each instance of the file service may identify and capture a command that changes the namespace structure and cause the change to be propagated to the other members of cluster. If one of the devices in the cluster does not successfully perform an update to the namespace structure, that device may be brought offline. The cluster based file service may permit adding or removing devices from the cluster while the file service is operating, and may provide a high throughput and high availability file service.

Clustered file service

Distributed storage defense in a cluster

The present invention extends to methods, systems, and computer program products for synchronizing state among load balancer components. Embodiments of the invention include load balancers using a consistent hashing algorithm to decide how new connections should be load balanced. Use of consistent hashing algorithm permits load balancers to work in a stateless manner in steady state. Load balancers start keeping flow state information (destination address for a given flow) about incoming packets when it is needed, i.e. such as, for example, when a change in destination host configuration is detected. State information is shared across load balancers in a deterministic way, which allows knowing which load balancer is authoritative (e.g., is the owner) for a given flow. Each load balancer can reach the authoritative load balancer to learn about a flow that cannot be determined locally.

Synchronizing state among load balancer components

Embodiments are directed to creating global, aggregated namespaces for storage management and to providing consistent namespaces in a distributed storage system. In one scenario, a computer system defines data storage objects for each data storage node. The data storage objects uniquely identify storage elements of the data storage nodes, where each data storage object includes various associated attributes. The computer system replicates the defined data storage objects and any associated attributes from a first data storage node to a second, different data storage node among the data storage nodes. As such, the defined data storage objects are visible from any node in the data storage nodes. The computer system also aggregates the defined data storage objects for each of the data storage nodes and creates a global, aggregated namespace that includes the aggregated data storage objects for each of the data storage nodes.

Creating global aggregated namespaces for storage management

The representation of storage devices on computers (e.g., as logical volumes) may be complicated by the pooling of multiple storage devices in order to apply redundancy plans such as mirroring and checksumming. Presented herein is a storage device driver configured to operate as a storage device interface generating representations of the storage regions of the storage devices; to claim those regions as a storage controller; and to expose pooled storage regions as logical disks. Additionally, the storage device driver may support the inclusion of storage devices in a cluster, comprising nodes that may be appointed as managers of the storage pool configuration; as managers of the storage devices; as owners having exclusive read/write access to the storage pool or cluster resources; and as cluster resource writers having exclusive write access to a cluster resource. The nodes of the cluster may interoperate to share the storage devices while avoiding write conflicts.

Storage device drivers and cluster participation

The present invention extends to methods, systems, and computer program products for implementing persistent reservation techniques for establishing ownership of one or more physical disks. These persistent reservation techniques can be employed to determine ownership of physical disks in a storage pool as well as in any other storage configuration. Using the persistent reservation techniques of the present invention, when a network partition occurs, a defender of a physical disk does not remove a challenger's registration key until the defender receives notification that the challenger is no longer in the defender's partition. In this way, pending I/O from applications executing on the challenger will not fail due to the challenger's key being removed until the proper ownership of the physical disk can be resolved.

Growing community of inventors

Sammamish, WA, United States of America

Vyacheslav Kuznetsov