Abstract: In an embodiment of the present disclosure, a processor receives a request to create a volume, wherein a volume placement policy comprises a plurality of scheduler algorithms, each of the scheduler algorithms selecting one or more worker nodes from a plurality of worker nodes for volume storage, determines, based on output from the plurality of scheduler algorithms, the one or more worker nodes, wherein output of each of the plurality of scheduler algorithms is assigned a weight in determining the one or more worker nodes; and causes a node agent in each of the one or more worker nodes to create the volume.

Abstract: Machine implemented methods and systems for writing data at a storage device are provided. A write command from an initiator adapter is received at a target adapter interfacing with a target controller for writing data to the storage device; where the write command includes information regarding a virtual logical unit number (LUN) for writing data in response to the write command. The target controller uses an indicator to notify the target adapter to process the write command and provides information regarding a designated LUN for the storage device where data is to be written at the storage device in response to the write command. Thereafter, the target adapter sends a response to the initiator adapter that it is ready to receive data and issues a write command for the storage device at the same time.

Abstract: Methods and systems for processing an input/output (I/O) requests are provided. The method includes generating an I/O request by an initiator adapter of a computing device that interfaces with a target adapter; indicating by the initiator adapter that the I/O request is sequential in nature. When the I/O request is a sequential read request, the target adapter notifies a target controller to read-ahead data associated with other sequential read requests; and stores the read ahead data at a cache such that data for the other sequential read requests is provided from the cache instead of a storage device managed by the target controller. A sequential write request is processed without claiming any cache space, when data for the write request is not to be accessed within a certain duration.

Abstract: Machine implemented method and system for processing a write request for a copy on write (COW) enabled write operation to write to a logical unit number (LUN) for which a replicated LUN exists is provided. An adapter coupled to a computing system and interfacing with the LUN and the replicated LUN receives the write request having an indicator indicating that the write request is for the COW enabled write operation. The adapter issues a read request to the LUN to read previous information from the LUN; temporarily stores the previous information at a memory storage location of the adapter; writes the previous information to the replicated LUN; writes the information based on the write request to the LUN; and notifies the computing system indicating that the write request for the COW enabled write operation has been completed.

Abstract: Techniques for CDP/R services are disclosed. In one particular exemplary embodiment, the techniques may be realized as a method of transitioning continuous data protection and replication comprising determining whether a first appliance node connected to a switched fabric contains one or more transactions received from a host node, unregistering a world wide port name of a target port of the first appliance node, registering the world wide port name to a target port of a second appliance node connected to the switched fabric, associating one or more logical unit numbers of the second appliance node with the target port of the second appliance node, exporting the one or more logical unit numbers of the second appliance node, logging the target port of the second appliance node into a switched fabric, and logging the target port of the second appliance node into a remote node port of the host node.

Abstract: Techniques for proactive synchronization of backups on replication targets are disclosed. In one particular exemplary embodiment, the techniques may be realized as a method for proactive synchronization of a backup on a replication target comprising reading a stored replication request to obtain replication data address information, sending the replication data address information to a replication target, receiving the replication data address information at the replication target, and copying data associated with the received replication data address information to a backup.

Abstract: Applications executing on various nodes in a distributed storage environment may write data to primary storage and may also replicate the data to secondary storage via a replication target. An interval coordinator may coordinate the periodic saving of checkpoints or snapshots of the replicated data. The interval coordinator may determine the length of consistency intervals between the saving of each of the checkpoints. Writes to the replication target from each of the nodes may be associated with the current consistency interval and, in some embodiments, with a unique per-node sequence number. When transitioning between consistency intervals, each node may be configured to temporarily suspend completion of the writes and to send the replication target a consistency interval marker indicating that the node has completed all writes for the current consistency interval.

Abstract: In-band commands may be associated with a particular consistency interval and may indicate requested actions to be performed for that consistency interval. An application may desire to perform actions, such as additional backup, snapshots, etc. on stored data, when that data is in a consistent state from the application's point of view. In order to ensure that the data is in a consistent state, a consistency interval may be created on demand. A node may request a consistency interval by sending a consistency request message to a consistency interval coordinator, which in turn, establishes the consistency interval with all nodes in the distributed environment. After sending all write requests for the consistency interval, the node may then send the command message. Command messages may be stored in consistency logs along with write requests and a replication target, or other device, may read both the write requests and the command message.

Abstract: Techniques for reducing data storage needs using continuous data protection and replication are disclosed. In one particular exemplary embodiment, the techniques may be realized as a method for reducing data storage needs using a continuous data protection and replication device comprising creating a master image of material identified by a user, generating a virtual replica of the master image on a storage area network using the continuous data protection and replication device to virtualize physical storage containing the master image, generating a copy of the virtual replica on the storage area network, and providing a virtual logical unit number to access the copy, wherein the access enables a process which requires exclusive access to content of the master image to obtain such access without requiring physical storage for an entire copy of the master image.

Abstract: A method involves detecting that a first storage device is inaccessible. The information stored on the first storage device is a synchronized copy of information stored on a second storage device. In response to detecting that the first storage device is inaccessible, modification logging is initiated. Modification logging involves detecting modifications to information stored on the second storage device and storing information that indicates an order in which the modifications occur to the second storage device. The stored information can indicate the order explicitly (e.g., by including a timestamp or sequence number) or indirectly (e.g., the order of entries stored in a log can indicate the order of the modifications represented by those entries). The stored information can also include the new values generated by the modifications. The stored information can then be used to resynchronize the information stored on the first and second storage devices.

Abstract: In distributed storage environments, nodes may send replicated writes for temporal volumes and may be configured to request on-demand consistency intervals in order to allow multiple nodes to transition between timestamps for temporal data in a uniform and coordinated manner. In response to a request from a node for a consistency interval transition, a consistency interval coordinator may end a current consistency interval and start another and may provide coordination to various nodes to enable the nodes to transition from one timestamp to another, and thus from one temporal version to another, while prevent data corruption or inconsistency between the temporal versions. Additionally, periodic consistency intervals may be utilized to provide consistent and coordinated transitions between temporal timestamps. In some embodiments, replicated writes including temporal timestamp information may be stored persistent spillover logs allowing offline updating and versioning of data to temporal volumes.

Abstract: Various systems and methods are disclosed for applying incremental changes prior to initialization of a point-in-time copy. For example, one method involves identifying an incremental change to information stored on a primary device. The incremental change is identified subsequent to a first point in time. The incremental change is applied to a first target device, prior to completing initialization of a second target device. The initialization of the second target device initializes the second target device as a point-in-time copy of the primary device. The point-in-time copy of the primary device is a copy of the primary device at the first point in time.

Abstract: One goal of consistency interval replication is to achieve a consistent copy of data generated by independent streams of writes from nodes in a clustered/distributed environment. Two writes to the same block from different nodes may arrive at a replication target in a different order from the order in which they were written to primary storage. A consistency interval coordinator may analyze a list of blocks modified during a consistency interval to determine conflict blocks written to by two different nodes during the same consistency interval. Conflict resolution may involve a node reading data for a conflict block from primary storage and forwarding it to the replication target or a node completing a suspended in-progress write for the conflict block. Once the conflicts have been resolved, the replication target may checkpoint the data modified during the interval and nodes may resume writes to the conflict blocks for the new interval.

Abstract: A method and system of providing periodic replication is disclosed. According to one embodiment, a method is provided which comprises creating a storage object corresponding to a storage volume, wherein the storage object comprises a point-in-time copy of the storage volume and a storage volume map; and replicating the storage volume using the storage object.

Abstract: A system for optimizing storage operations by operating only on mapped blocks may include a first and a second set of one or more storage devices, a virtual device client and a virtual device server. The virtual device server may be configured to aggregate storage in the first set of one or more storage devices into a virtual storage device, and make the virtual device accessible to the virtual device server. In preparation for a synchronization operation, the virtual device server may obtain a map identifying one or more in-use regions of the virtual storage device from the virtual device client. The virtual device server may then perform the synchronization operation by copying the one or more in-use regions of the virtual storage device to the second set of one or more storage devices.

Abstract: A method and system of providing periodic replication is disclosed. According to one embodiment, a method is provided which comprises creating a storage object corresponding to a data volume, wherein the storage object comprises a point-in-time copy of the data volume and a data volume map; and replicating the data volume utilizing the storage object.