Microsoft Technology Licensing, LLC

Brocade Communications Systems, Inc.

Veritas Software Corporation

Vinod R Shankar

Andrea D'Amato

Karan Mehra

Vladimir Petter

Vyacheslav Kuznetsov

Eric Lindvall

Peter Benoit

Xinhong (Henry) Zhang

Taylor Alan Hope

David Allen Dion

Alan M Warwick

Emanuel Paleologu

Justin Sing Tong Cheung

Slava Kuznetsov

Joydeep Buragohain

Sarosh Cyrus Havewala

Rajsekhar Das

Scott Chao-Chueh Lee

Grigory Borisovich Lyakhovitskiy

Bryan Stephen Matthew

Kiran Kumar G Bangalore

Data is identified that defines a known good state for a current operating system. The identified data includes read-only sets that are not updated during operation of the computing device, and modifiable sets that can be updated during operation of the computing device. The read-only sets are captured on an opportunistic basis and the modifiable sets are captured when the computing device is to be rebooted. A first and second virtual disk are allocated as snapshots of the identified data. The first virtual disk is updated to generate an updated state. The updates to the first virtual disk are isolated from the second virtual disk. The second virtual disk is maintained as an immutable snapshot of the identified data. In response to a failed reboot with the updated state, the computing device reverts to the known good state using the snapshot of the identified data.

Space snapshots

A data storage array is configured for m-way resiliency across a first plurality of storage nodes. The m-way resiliency causes the data storage array to direct each top-level write to at least m storage nodes within the first plurality, for committing data to a corresponding capacity region allocated on each storage node to which each write operation is directed. Based on the data storage array being configured for m-way resiliency, an extra-resilient cache is allocated across a second plurality of storage nodes comprising at least s storage nodes (where s&#x3e;m), including allocating a corresponding cache region on each of the second plurality for use by the extra-resilient cache. Based on determining that a particular top-level write has not been acknowledged by at least n of the first plurality of storage nodes (where n m), the particular top-level write is redirected to the extra-resilient cache.

Extra-resilient cache for resilient storage array

A first storage node configured to store data associated with a user is allocated. The data stored on the first storage node is mirrored at a second storage node. A resiliency mechanism is implemented at the first and second storage nodes. The resiliency mechanism is configured to restore data on at least one of the storage devices of the first and second storage nodes. In response to a loss of availability of either the first or second storage node and a loss of availability of one or more storage device on an available storage node, data on the unavailable storage devices of the available storage node is recovered using the resiliency mechanism of the available storage node.

Multilevel resiliency

A virtual disk is instantiated as a representation of a storage volume. The virtual disk is configured with metadata corresponding to the storage volume. A storage stack is instantiated that is operable to provide an active I/O path to the storage volume. The storage stack is modified by adding an alternative I/O path to the virtual disk. The alternative I/O path includes a layout driver configured to manage a converted storage layout for the storage volume. The storage volume is encapsulated to the virtual disk. The active I/O path is closed and the alternative I/O path is enabled for I/O requests to the virtual disk. The storage layout of the storage device is converted without taking the storage volume offline.

Online conversion of storage layout

A data store is accessed that stores a collected historical record of performance metrics for input/output operations executed at a storage device that is part of a group of storage devices that are configured to provide a fault resiliency function. A performance profile is determined for the selected storage device based on selected performance metrics of the historical record. A difference between the performance profile for the storage device and a characteristic performance profile for similar storage devices is determined. When the difference exceeds a predetermined deviance threshold, selected I/O requests designated for the selected storage device are redirected to another device of the group of storage devices.

Timeout mode for storage devices

A system is configured to use a de-randomizer and budget data structure to economize I/O operations for a shared storage device while still allowing access to the device to a number of different entities. Embodiments can identify a comparatively low cost next operation as compared to other I/O operations, including a cost for seek time, for a first entity to dispatch to the storage device when the first entity has sufficient budget to have the I/O operation performed on its behalf and to identify an I/O operation for a second entity to dispatch to the storage device when there is insufficient budget for the first entity.

Storage device access mediation

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

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

The techniques disclosed herein provide a dynamically configurable cluster of storage devices. In some configurations, the dynamically configurable cluster is associated with a fault domain. The cluster may include a plurality of computing devices that each include at least a storage device. The plurality of storage devices in the cluster may be configured to support a plurality of workloads coupled to the dynamically configurable cluster. The plurality of storage devices in the dynamically configurable cluster may be allocated to one or more of the plurality of workloads based on metadata identified resiliency requirements, performance requirements, and/or cost factors linked to the one or more of the plurality of workloads.

Dynamically configurable storage clusters

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

Distributed storage defense in a cluster

The targeted recovery of application-specific data corresponding to an application without performing recovery of the entire volume. The recovery is initiated by beginning to copy the prior state of the content of an application-specific data container from a prior snapshot to the application-specific data container in an operation volume accessible by the application. However, while the content of the application-specific data container is still being copied from the snapshot to the application-specific data container, the application is still permitted to perform read and write operations on the application-specific data container. Thus, the application-specific data container appears to the application to be fully accessible even though recovery of the content of the application-specific data container is still continuing in the background.

Recovery of application from snapshot

Implementing point in time back-up. A method that may be practiced in a distributed computing environment. The distributed computing environment includes a number of computing system nodes. The method includes at a first node in the computing environment, taking a snapshot of a cluster volume. The cluster volume stores data items (e.g. files/blocks). Taking a snapshot includes marking a point in time for data items in the volume. The method further includes receiving a notification that a different node in the computing environment than the first node, has determined to change a data item in the cluster volume at a point after the marked point in time from an old version of the data item to a new version of the data item. The method further includes at the first node, saving the old version of the data item prior to modification.

Backup and restore of data from any cluster node

Coordinating methods of I/O access to a shared data store. A method includes at a node, in a distributed system, performing one or more I/O operations on the shared data store using direct I/O access on a virtual data container. Direct I/O access includes performing I/O operations directly from the node to the shared data store including not having an owner node perform the I/O operation on the shared data store on the node's behalf. The owner node is a different node than the node doing the direct I/O operation. The owner node accesses the shared data store through a local data container. The method further includes determining that one or more subsequent I/O operations should be performed using redirected I/O access, where I/O operations are directed through a centralized node. The method further includes indicating to nodes in the distributed system to switch to redirected I/O access method.

Growing community of inventors

Woodinville, WA, United States of America

Vinod R Shankar