Abstract: Various embodiments of systems and methods are disclosed for performing online backup and restore of volume configuration information. In some embodiments, a method involves receiving a request to restore a volume configuration and, in response to the request, writing volume configuration information to a storage device. The volume configuration information includes a first disk signature, which identifies the storage device.

Abstract: A method, system, computer system, and computer program produce to support a distributed environment in which changes to data shared by multiple nodes are logged using private logs and managed by a coordinator. The coordinator recognizes invalidating operations and informs a reader when data need to be read again after an invalidating operation corrupted and/or caused the copy of the data read by the reader to be out-of-date. The coordinator can provide a location from which current valid data can be read. The coordinator can use an operations history to detect invalidating operations and operations trackers to determine when a node is not synchronized with the coordinator.

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: Disclosed is a method and apparatus for restoring a corrupted data volume. In one embodiment, the method includes creating a backup copy of the data volume before the data volume is corrupted. Data transactions that modify the contents of the data volume are stored in a transaction log. After detection of the data corruption, a virtual copy of the backup copy is created. Thereafter, select data transactions stored in the transaction log, are applied to the virtual copy. Data of the corrupted data volume is then overwritten with data of the backup copy and data of the virtual copy after applying data transactions to the virtual copy.

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: Systems and methods for I/O fencing in a shared storage environment are provided. Prior to initiating an I/O request, when feasible, the current time from a local timer is compared to the current state of an interval obtained for the target device. As a result, a device reset occurring while the interval is viable does not arbitrarily end a multiphase I/O operation. However, a device reset occurring once the lease has expired results in a delay or termination of the multiphase I/O operation. As a result, multiphase I/O operations from initiating hosts that have lost contact with the shared storage environment are not allowed to corrupt the shared 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.

Abstract: Disclosed is a method and apparatus for replicating a data volume using a network appliance. In one embodiment, a first node transmits a first write-data transaction to a first data storage system and to the network appliance. A second node transmits a second write-data transaction to the first data storage device and to the network appliance. The network appliance transmits the first and second write-data transactions to a third node via a communication link for updating a replica of a data volume. The data volume is stored in the first data storage system and is updated with first and second data contained in the first and second write-data transactions, respectively. The replica of the data volume is stored in a second data storage system and is updated with the first and second data.

Abstract: A first read request is received from a computer system. Data from one mirror of a data volume is returned to the computer system in response to receiving the first read request. The computer system may check the returned data to determine whether it is corrupted. If corrupted, the computer system sends a second read request for the same data. Rather than returning the same corrupted data stored in the one mirror, a copy of the requested data is returned from an alternate mirror of the data volume.

Abstract: A method, system, and computer program product for adaptively implementing capabilities of a logical volume. If a particular capability is an inherent attribute of an existing storage device, the existing storage device is chosen to implement the volume. If the particular capability is not an inherent attribute of an existing storage device, one or more storage devices are selected and configured to provide the capability. If a capacity is requested for the logical volume and a storage device provides only a portion of the capacity, multiple storage devices having the capability are combined to provide the requested capability and capacity.

Abstract: A method, system, language, and computer program product to enable a user to provide a high-level specification of storage requirements without having detailed knowledge of the underlying vendor-specific APIs and command line utilities for each possible storage device used to meet the storage requirements. The user does not specify how to implement the storage requirements. The system implements the high-level specification in hardware and/or software without further direction from the user.

Abstract: A method, system, computer system, and computer program product to support a distributed environment in which changes to data shared by multiple nodes are logged using private logs and managed by a coordinator. The coordinator recognizes invalidating operations and informs a reader when data need to be read again after an invalidating operation corrupted and/or caused the copy of the data read by the reader to be out-of-date. The coordinator can provide a location from which current valid data can be read. The coordinator can use an operations history to detect invalidating operations and operations trackers to determine when a node is not synchronized with the coordinator.

Abstract: A method, system, and computer program product for preserving the intent of a logical volume creator with the logical volume. The creator of a logical volume defines certain characteristics of that logical volume. In response to the user's requirements, the system explores the possibilities for providing the characteristics in the existing storage environment. The system then implements the logical volume and stores the intent, along with a corresponding set of rules for configuring the logical volume, with the logical volume. As a result, volume management operations like resizing the volume and evacuating data from the volume use the rules to preserve the intent of the creator. By ensuring that the logical volume consistently conforms to rules fulfilling the original intent, a consistent level of availability of the logical volume can be achieved to fulfill contractual availability requirements for storage service level agreements.

Abstract: A method, system, and computer program product to enable a user to specify an intended use for a logical volume. The logical volume is configured using an application-specific template (also referred to as a user template) for an application, where the application-specific template satisfies the intended use. Rules from the application-specific template are stored with the logical volume in addition to or as part of the intent.

Abstract: A method, system, computer system, and computer-readable medium for maintaining up-to-date, consistent copies of primary data without the need to replicate modified data when the data were modified as a result of an operation that is not an application-driven write operation captured during replication. Selected storage management operations are performed on the primary and secondary data stores at points in time when the data are the same to ensure that the data stored within the data stores remain consistent. These selected storage management operations include operations that produce modified data stored in the primary data store, where a portion of the modified data are not replicated to a secondary node. Other types of storage management operations are selected to be performed on both the primary and secondary data stores, where the operations do not directly change data in the primary data store, but may affect data stored in the primary data store.

Abstract: Disclosed is an apparatus or method performed by a computer system for creating a hierarchy of data volumes. Each data volume in the hierarchy is a point-in-time (PIT) copy of another data volume in the hierarchy or a PIT copy of a data volume V. In one embodiment of the apparatus or method, the contents of a first data volume in the hierarchy can be refreshed to the contents of a second data volume in the hierarchy such that the first data volume becomes a PIT copy of the second data volume. Before the first data volume is fully refreshed to the contents of the second data volume, data of the first data volume can be read or modified.

Abstract: In a system in which read data tracking and caching is used to recover from data corruption, a first request to read data from a primary data mirror is received from a computer system. Data is read from the primary data mirror in response to receiving the first request. Additionally data from a mirrored copy of the primary data mirror is read. Data read from the primary data mirror is returned to the computer system. Data read from the mirrored copy is stored into a memory device. If a second request is received from the computer system to read the same data of the first request, data stored in the memory device may be returned in response thereto.

Abstract: A method may involve: an application executing on a host initiating a write to a stripe in a storage volume; in response, the host requesting permission from a coordinator to perform the write to a set of data (e.g., a stripe or other group of data from which redundant information is calculated according to a RAID protocol) in a storage volume; prior to receiving permission to write to the storage volume from the coordinator, the host initiating storage of write data associated with the write to an associated one of a plurality of logs; the host waiting before performing the write to the storage volume; and, if one or more additional writes targeting the same set of data (e.g., the same stripe) are initiated while waiting, the host combining redundant information (e.g., parity) calculations for the writes into a single redundant information calculation.

Abstract: In a system in which read data tracking and caching is used to recover from data corruption, a first request to read data from a primary data mirror is received from a computer system. Data is read from the primary data mirror in response to receiving the first request. Additionally data from a mirrored copy of the primary data mirror is read. Data read from the primary data mirror is returned to the computer system. Data read from the mirrored copy is stored into a memory device. If a second request is received from the computer system to read the same data of the first request, data stored in the memory device may be returned in response thereto.

Abstract: Disclosed is a method and apparatus for restoring a corrupted data volume. In one embodiment, the method includes creating a backup copy of the data volume before the data volume is corrupted. Data transactions that modify the contents of the data volume are stored in a transaction log. After detection of the data corruption, a virtual copy of the backup copy is created. Thereafter, select data transactions stored in the transaction log, are applied to the virtual copy. Data of the corrupted data volume is then overwritten with data of the backup copy and data of the virtual copy after applying data transactions to the virtual copy.