Abstract: Techniques for recovering from a failure at a disaster recovery site are disclosed. An example method includes receiving an indication to shift control of a set of volumes of a plurality of volumes. The set of volumes is originally owned by a second storage node. The first storage node is a disaster recovery partner of the second storage node. The method includes shifting control of the set of volumes. The method further includes during the shifting, changing a status of a flag corresponding to a progress of the shifting. The method also includes during a reboot of the first storage node, determining the status of the flag and determining, based on the status of the flag, whether to mount the set of volumes during reboot at the first storage node.

Abstract: A method performed by a monitoring tool in a computer system, the method including: for a set of network nodes in a computer system: applying a correlation formula on an input based on performance data of the set, and determining a correlation score based on applying the correlation formula, the correlation score indicating a correlation between network nodes in the set; determining, based on the correlation scores, a first list including a first plurality of network nodes having a correlation score that satisfies a first threshold; identifying a second plurality of network nodes included in the first list, the second plurality of network nodes having a correlation score that satisfies a second threshold, which indicates a correlation that is higher than the first threshold; analyzing the performance data of the second plurality against a constancy metric; and removing, based on the analyzing, the second plurality from the first list.

Abstract: Methods and apparatuses for updating members of a data storage reliability group are provided. In one exemplary method, a reliability group includes a data zone in a first storage node and a checksum zone in a second data storage node. The method includes updating a version counter associated with the data zone in response to destaging a data object from a staging area of the data zone to a store area of the data zone without synchronizing the destaging with the state of the checksum zone. The method further includes transmitting, from the data zone to the checksum zone, an update message indicating completion of the destaging of the data object, wherein the update message includes a current value of the version counter.

Abstract: A network-based storage system includes multiple storage devices and system controllers. Each storage device in multiple aggregates of storage devices can include ownership portion(s) that are configured to indicate a system controller to which it belongs. First and second system controllers can form an HA pair, and can be in communication with each other, the storage devices, and a separate host server. A first system controller controls an aggregate of storage devices and can facilitate an automated hotswap replacement of a second system controller that controls another aggregate of storage devices with a separate third system controller that subsequently controls the other aggregate of storage devices.

Abstract: In one embodiment, a node of a cluster is coupled to a storage array of storage devices. The node executes a storage input/output (I/O) stack having a redundant array of independent disks (RAID) layer that organizes the storage devices within the storage array as a plurality of RAID groups. Configuration information is stored as a cluster database. The configuration information identifies the RAID groups associated with the storage devices. Each RAID group is associated with a plurality of segments and each segment has a different RAID configuration.

Abstract: The present invention is a method for accelerating proxy Input/Output (proxyI/O). The method includes the step of receiving a command at a primary target storage system. The primary target storage system may be part of a clustered storage array. The command may be a command which was transmitted by an initiator system via a storage area network, and may include a request for data. The method further includes the step of forwarding the command to a session layer of the primary target storage system. Further, when a virtualization layer of the primary target storage system determines that a portion of the data requested in the data request is not stored by the primary target storage system, but is stored by a proxy target storage system included in the plurality of storage systems, the method further includes providing a proxyIO request to a proxy initiator of the primary target storage system.

Abstract: One or more techniques and/or systems are provided for mirror vote synchronization. For example, a first storage device is located at a first storage site, and a second storage device is located at a second storage site. The second storage device is configured according to a data mirroring configuration where data from the first storage device is mirrored to the second storage device. Mirror vote metadata is generated based upon an up-to-date state of the data mirroring configuration. The mirror vote metadata indicates whether the first storage device and/or the second storage device are up-to-date or not. The mirror vote metadata may be replicated between the first storage site and the second storage site. If the first storage site fails, then the second storage site may provide switchover operation using the second storage device based upon the mirror vote metadata.

Abstract: A method of power management of a multiple-data-storage-devices enclosure is disclosed.

Abstract: Systems and methods that allow operators to configure how files and directories are placed within file system views into a storage system, and how these configured file placements are performed by the distributed system. Possible features include a mechanism by which the desired placement of files and directories can be specified, a mechanism by which the placement goals can be realized in a given topology of a distributed system, and a mechanism by which changes to the placement of objects can applied retroactively. The disclosed embodiments may be able to scale to managing hundreds of billions of files spanning thousands of file system views, especially in the presence of disconnected operation.

Abstract: Region based admission and eviction control can be used for managing resources (e.g., caching resources) shared by competing workloads with different SLOs in hybrid aggregates. A “region” or “phase” refers to different incoming loads of a workload (e.g., different working set sizes, different intensities of the workload, etc.). These regions can be identified and then utilized along with other factors (e.g., incoming loads of other workloads, maximum cache allocation size, service level objectives, and others factors/parameters) in managing cache storage resources.

Abstract: Fault isolation capabilities made available by user space can be provided for a embedded network storage system without sacrificing efficiency. By giving user space processes direct access to specific devices (e.g., network interface cards and storage adapters), processes in a user space can initiate Input/Output requests without issuing system calls (and entering kernel mode). The multiple user spaces processes can initiate requests serviced by a user space device driver by sharing a read-only address space that maps the entire physical memory one-to-one. In addition, a user space process can initiate communication with another user space process by use of transmit and receive queues similar to transmit and receiver queues used by hardware devices. And, a mechanism of ensuring that virtual addresses that work in one address space reference the same physical page in another address space is used.

Abstract: A network attached storage (NAS) caching appliance, system, and associated method of operation for caching a networked file system. Still further, some embodiments provide for a cache system that implements a mufti-tiered, policy-influenced block replacement algorithm.

Abstract: A policy framework is maintained on the computing device, and the computing device communicates with a policy server of an enterprise network over a network to receive a set of policy instructions. The policy instructions are executed through the policy framework in order to implement one or more policies that control the mobile computing device's access to resources of the enterprise network.

Abstract: According to one or more embodiments of the present invention, a network cache intercepts data requested by a client from a remote server interconnected with the cache through one or more wide area network (WAN) links (e.g., for Wide Area File Services, or “WAFS”). The network cache stores the data and sends the data to the client. The cache may then intercept a first write request for the data from the client to the remote server, and determine one or more portions of the data in the write request that changed from the data stored at the cache (e.g., according to one or more hashes created based on the data). The network cache then sends a second write request for only the changed portions of the data to the remote server.

Abstract: A service system can include numerous test scripts that are candidates for execution against a failure message to determine a solution for a failure in a distributed storage system. To efficiently ascertain a solution for a failure with the test scripts, a service system can analyze the failure message to determine tags and use the tags to guide selection of test scripts. The selected test scripts are then executed to analyze the failure message, and to generate, based on the analysis, a solution corresponding to the failure. Instead of executing the numerous test scripts against the failure message, only selected test scripts are executed against the failure message to generate a solution. The solution is then communicated to the distributed storage system.

Abstract: Technology for accessing previous versions of data objects within a storage cluster including multiple storage volumes under a common namespace is disclosed herein. In some embodiments, the network storage cluster having multiple cooperative storage nodes receives a namespace identifier for a previous version of a data object. The namespace identifier includes a namespace path containing a volume junction and a time indicator indicating a point in time when the previous version of the data object existed. The network storage cluster identifies a storage volume within the network storage cluster using the volume junction. The volume junction points to a root directory of a file system of the storage volume. The network storage cluster locates, based on the namespace path, the previous version of the data object within a snapshot copy of the storage volume, wherein the snapshot copy is identified by the time indicator.

Abstract: One or more techniques and/or systems are provided for interconnect failover between a primary storage controller and a secondary storage controller. The secondary storage controller may be configured as a backup or failover storage controller for the primary storage controller in the event the primary storage controller fails. Data and/or metadata describing the data (e.g., data and/or metadata stored within a write cache) may be mirrored from the primary storage controller to the secondary storage controller over one or more interconnect paths. Responsive to identifying a failover trigger for a failed interconnect path, the secondary storage controller is instructed to fence (e.g., block) I/O operations from the failed interconnect path. Streams of data and/or metadata that were affected by the failure may be instructed to transmit such data and/or metadata over one or more non-failed interconnect paths to the secondary storage controller during failover of the failed interconnect path.

Abstract: A storage controller receives data from a host. The data is provided to a storage stack on the storage controller. The storage stack can perform deduplication, compression or file layout operations on the data, which is then written to a first storage unit coupled to a first port of the storage controller. The storage controller determines whether a second port of the first storage controller is configured as a remote port. In response to determining that the second port is configured as a remote port, the data is also provided to a pass-thru stack on the first storage controller. The pass-thru stack performs protocol conversion on the data and writes the data to the second port on the storage controller.

Abstract: Systems and methods which provide an absent allocation technique with respect to absent data of a data structure for which data migration in a time-displaced data migration operation has not completed are disclosed. Through use of absent allocated data block states of an absent allocation technique of embodiments, dependency between source and destination data stores may be broken. An absent allocated data block state of embodiments stored within the data structure provides a suggestive indication that data of a data block of a data structure is absent from the data structure. A corresponding absent allocated data block state of embodiments stored external to the data structure provides a determinative indication that the data of the data block of the data structure is absent from the data structure. The absent data block determinative indictor of embodiments is updated as data continues to be migrated.

Abstract: A storage device failure in a computer storage system can be analyzed by the storage system by examining relevant information about the storage device and its environment. Information about the storage device is collected in real-time and stored; this is an on-going process such that some information is continuously available. The information can include information relating to the storage device, such as input/output related information, and information relating to a storage shelf where the storage device is located, such as a status of adjacent storage devices on the shelf. All of the relevant information is analyzed to determine a reason for the storage device failure. Optionally, additional information may be collected and analyzed by the storage system to help determine the reason for the storage device failure. The analysis and supporting information can be stored in a log and/or presented to a storage system administrator to view.