Abstract: A method begins by a processing module receiving a data storage request, wherein the data storage request includes data and a data identifier (ID). The method continues with the processing module dispersed storage error encoding the data to produce a set of encoded data slices and determining a data dispersed storage network (DSN) address. The method continues with the processing module sending the set of encoded data slices to a DSN memory for storage at the data DSN address and updating a directory file with path information corresponding to the data ID and the data DSN address to produce an updated directory file. The method continues with the processing module dispersed storage error encoding the updated directory file to produce a set of encoded updated directory slices and sending the set of encoded updated directory slices to the DSN memory for storage at a directory DSN address.

Abstract: A method includes detecting that a first file and a second file are duplicates, and storing the first file and the second file to a target storage device. Metadata is written to the target storage device in association with the first file, wherein the metadata identifies the location of the second file that is a duplicate of the first file. Later, an application program requests a first read operation to read the first file. In response to a media error that results from the first read operation, the target storage device reads the metadata associated with the first file to identify the location of the second file, performs a second read operation to read the second file instead of the first file, and provides the second file to the application program in satisfaction of the requested first read operation.

Abstract: An array can include a controller and multiple storage devices of a first type. When a storage device of the first type is replaced by a replacement storage device of a second type, and other storage devices of the first type remain in the array, the controller instructs the replacement storage device to configure itself as a storage device of the first type. When the last storage device of the first type in the array is replaced by a replacement storage device of the second type, the controller instructs all the storage devices of the array to configure themselves as storage devices of the second type.

Abstract: The invention relates to apparatus for managing data swap in a migration of virtual memory data of a virtual machine. In one embodiment, an apparatus comprises a receiving unit configured to receive a migration instruction and the second site information; a copying unit configured to copy memory data to a sub-logical unit in the first storage device; and a notifying unit configured to send a notification to instruct the second host to read the memory data from a mirror logical unit of a sub-logical unit in the second storage device. The apparatus modifies a mirror direction between the first and second storage devices and modifies a path table related to the first and second storage devices. Data of the virtual machine can be migrated and swapped in a metro mirror manner, thereby the virtual machine data can be migrated across sites without affecting system operation.

Abstract: One aspect of the present invention provides a system for failover comprising at least one client selectively connectable to one of at least two interconnected server via a network connection. In a normal state, one of the servers is designated a primary server when connected to the client and a remainder of the servers are designated as backup servers when not connected to the client. The at least one client is configured to send messages to the primary server. The servers are configured to process the messages using at least one service that is identical in each of the servers. The services are unaware of whether a server respective to the service is operating as the primary server or the backup server. The servers are further configured to maintain a library, or the like, that indicates whether a server is the primary server or a server is the backup server. The services within each server are to make external calls via its respective library.

Abstract: In one embodiment, a method for managing data swapping in a migration of virtual memory data in a virtual machine, wherein the data swapping is from a first storage device at a first site to a second storage device at a second site, and the first and second storage devices have a metro mirror relationship includes sending a fail report in response to a failure to access the first storage device according to a path table, in response to the fail report, modifying a mirror direction between the first and second storage devices, sending a path modifying notification for modifying settings of a first path to the second storage device, and activating the path to the second storage device by modifying the path table according to the path modifying notification, so as to make the second storage device accessible.

Abstract: A method begins by a processing module receiving data for storage and interpreting the data to identify the data as redundant array of independent disks (RAID) data. The method continues with the processing module interpreting the RAID data to identify at least one of RAID block data and RAID parity data. When the RAID data includes RAID block data and RAID parity data the method continues with the processing module encoding the RAID block data in accordance with error coding dispersal storage function parameters to produce at least one set of encoded data slices and outputting the at least one set of encoded data slices to a dispersed storage network memory.

Abstract: Subject matter disclosed herein relates to determining that a portion of a memory is at least partially non-functional, replacing the portion of at least partially non-functional memory; and adjusting an error detection and/or correction process responsive to determining that the portion of the memory is at least partially non-functional and/or replacing the portion of at least partially non-functional memory.

Abstract: In one aspect, a method includes replicating multiple volumes synchronously across storage arrays using data protection agents, determining that a component has failed, trying to recover replication using another component and, if recovery of replication is not possible for a predetermined amount of time, stopping replication for all replicated volumes at a consistent point.

Abstract: An improved technique applies polar codes to storage data to improve the reliability of a storage system that uses high-performance, solid-state disks as part of a RAID group for storing frequently-accessed data. Along these lines, a high-performance storage system having n solid-state disks assigns k of those disks as payload disks. The storage system partitions the payload data into a data vector that has k data symbols. The storage system then applies, to the k payload symbols, a (n, k) polar code generator matrix derived from k rows of the ? log2 n?-times Kronecker product of the matrix ? ( 1 0 1 1 ) to produce n encoded symbols and stores each of the encoded payload symbols in a solid-state disk of the RAID group.

Abstract: Information processing system for rapidly performing analysis of semistructured data while preserving fault-tolerance of data for a store request acquiring the number which has been stored of the same and data structures set beforehand, refer to data structure management information to determine a data store unit, instructs replica creation of the data with regard to the data stored in the data store unit in which any of the replicas have been stored, transmits an instruction, for performing a data operation, to a data structure operation unit, whereupon a processing unit, in accordance with the content of an analysis request, performs analysis processing by way of either data stored in any of the data storage units after a data structure operation or data which have not been subject to a data structure operation.

Abstract: A system, method, and computer program product provide a process that includes storing data on first data storage devices, and a backup copy of the data on the first and/or on second ones of the data storage devices. A probability of a failure of each of at least some of the first and/or second data storage devices is determined, and at least one of the first and/or data storage devices that is determined to have a higher probability of failure than a threshold and/or a probability of failure of another of the data storage devices, is selected. A second backup copy of the data, stored on the selected data storage device(s), is also stored on third ones of the data storage devices. The first and/or second data storage devices determined to have the higher probability of failure are used for their designated purpose after the second backup copy is created.

Abstract: A method for servicing a redundant array of independent storage drives (i.e., RAID) includes performing a service call on the RAID by performing the following steps: (1) determining whether the RAID includes one or more consumed spare storage drives; (2) in the event the RAID includes one or more consumed spare storage drives, physically replacing the one or more consumed spare storage drive with one or more non-consumed spare storage drives; and (3) initiating a copy process that copies data from a storage drive that is predicted to fail to a non-consumed spare storage drive associated with the RAID. The service call may then be terminated. After the service call is terminated, the method waits for an indication that a number of non-consumed spare storage drives in the RAID has fallen below a selected threshold. A corresponding apparatus and computer program product are also disclosed.

Abstract: A method and system for increasing server cluster availability by requiring at a minimum only one node and a quorum replica set of replica members to form and operate a cluster. Replica members maintain cluster operational data. A cluster operates when one node possesses a majority of replica members, which ensures that any new or surviving cluster includes consistent cluster operational data via at least one replica member from the immediately prior cluster. Arbitration provides exclusive ownership by one node of the replica members, including at cluster formation, and when the owning node fails. Arbitration uses a fast mutual exclusion algorithm and a reservation mechanism to challenge for and defend the exclusive reservation of each member. A quorum replica set algorithm brings members online and offline with data consistency, including updating unreconciled replica members, and ensures consistent read and update operations.

Abstract: A method and system for increasing server cluster availability by requiring at a minimum only one node and a quorum replica set of replica members to form and operate a cluster. Replica members maintain cluster operational data. A cluster operates when one node possesses a majority of replica members, which ensures that any new or surviving cluster includes consistent cluster operational data via at least one replica member from the immediately prior cluster. Arbitration provides exclusive ownership by one node of the replica members, including at cluster formation, and when the owning node fails. Arbitration uses a fast mutual exclusion algorithm and a reservation mechanism to challenge for and defend the exclusive reservation of each member. A quorum replica set algorithm brings members online and offline with data consistency, including updating unreconciled replica members, and ensures consistent read and update operations.

Abstract: A method for handling media errors during a read operation on a data storage device. The method comprises detecting that a first file and a second file are duplicates, wherein the first file is stored on a first storage device. Metadata is written to the first storage device in association with the first file, wherein the metadata identifies the location of the second file that is a duplicate of the first file. Later, an application program requests a first read operation to read the first file. In response to a media error that results from the first read operation, the method reads the metadata associated with the first file to identify the location of the second file, performs a second read operation to read the second file instead of the first file, and provides the second file to the application program in satisfaction of the requested first read operation.

Abstract: Handling failure of a primary group at a first data center that is part of plurality of data centers providing triangular asynchronous replication, includes creating a data mirroring relationship between at least one storage volume at a second data center having a synchronous backup group that is part of the plurality of data centers and at least one storage volume at a third data center having an asynchronous backup group that is part of the plurality of data centers and resuming work at the second data center. Handling failure of a primary group at a first data center may also include synchronizing the at least one storage volume at the second data center with the at least one storage volume at the third data center prior to resuming work at the second data center.

Abstract: In one embodiment, a method of coordinating data recovery in a storage stack with a hierarchy of layers includes, upon an input/output (I/O) request from a layer of the stack, issuing a help response to recover the data from a higher layer in hierarchy order. The method further includes processing the help response, at the higher layer, by issuing a return code of success or further help response to an even higher layer.

Abstract: A method, device, and computer readable medium for striping rows of data across logical units of storage with an affinity for columns is provided. Alternately, a method, device, and computer readable medium for striping columns of data across logical units of storage with an affinity for rows is provided. When data of a logical slice is requested, a mapping may provide information for determining which logical unit is likely to store the logical slice. In one embodiment, data is retrieved from logical units that are predicted to store the logical slice. In another embodiment, data is retrieved from several logical units, and the data not mapped to the logical unit is removed from the retrieved data.

Abstract: Systems and methods for redundant object storage are disclosed. A method may include storing at least two copies of each of a plurality of objects among a plurality of nodes communicatively coupled to one another in order to provide redundancy of each of the plurality of objects in the event of a fault of one of the plurality of nodes. The method may also include monitoring access to each object to determine a frequency of access for each object. The method may additionally include redistributing one or more of the copies of the objects such that at least one particular node of the plurality of nodes includes copies of only objects accessed at a frequency below a predetermined frequency threshold based on the determined frequency of access for each object. The method may further include placing the at least one particular node in a reduced-power mode.

Abstract: A method, system, and computer program product for restoring blocks of data stored at a corrupted data site using two or more mirror sites. The method commences by receiving a trigger event from a component within an application server environment where the trigger event indicates detection of a corrupted data site. The trigger is classified into at least one of a plurality of trigger event types, which trigger event type signals further processing for retrieving from at least two mirror sites, a first stored data block and a second stored data block corresponding to the same logical block identifier from the first mirror site. The retrieved blocks are compared to determine a match value, and when the match value is greater than a confidence threshold, then writing good data to the corrupted data site before performing consistency checks on blocks in physical or logical proximity to the corrupted data site.

Abstract: An information processing apparatus connecting a plurality of hard disks rebuilds data stored in one hard disk of the plurality of hard disks to another hard disk of the plurality of hard disks. The information processing apparatus is controlled in such a manner that when the information processing started, the rebuild is not resumed immediately after the information processing apparatus is started, and the rebuild is resumed after a predetermined time has elapsed.

Abstract: A method, computer program product, and storage network system for detecting a failure of a highly-available, volatile, solid state cache memory system included within a storage network. The highly-available, volatile, solid state cache memory system includes cache data. The cache data is replicated onto a non-volatile, solid-state, cache memory system included within the storage network. At least one data request concerning the highly-available, volatile, solid state cache memory system is redirected to the non-volatile, solid-state, cache memory system.

Abstract: When a primary computer is taken over to a secondary computer in a redundancy configuration computer system where booting is performed via a storage area network (SAN), a management server delivers an information collecting/setting program to the secondary computer before the user's operating system of the secondary computer is started. This program assigns a unique ID (World Wide Name), assigned to the fiber channel port of the secondary computer to allow a software image to be taken over from the primary computer to the secondary computer.

Abstract: The present invention relates to disk fault tolerance method, device and system which relates to a field of computer. The method comprises: receiving a file access request; acquiring one or more node lists corresponding to the file, wherein each node list comprises at least two nodes, and the mutually corresponding disks between the respective nodes store the same contents; accessing data chunks included in the file from the respective nodes selected from each of the node lists; and when an accessing from a certain node fails, selecting another node from the node list that comprises the certain node, and accessing a respective data chunk included in the file from the selected node according to the identifier of the file. The present invention proposes a multilevel pairing storage technology in combination with advantages of the dual machine duplexing mechanism, wherein a plurality of completely independent machines are mutually backed up from a node level to a disk level.

Abstract: A method, system and computer program product for data replication comprising receiving an IO at a first storage processor (SP), sending metadata corresponding to the IO to a second SP, receiving an acknowledgement from the second SP indicating the second SP received the metadata and send the IO down an IO stack.

Abstract: In one embodiment, a first computing device receives a write request and data from a second computing device; iteratively attempts to write the data until a copy of the data is successfully written to each and every storage node belonging to a storage volume; and transmits a volume identifier of the storage volume and a data identifier assigned to the data to the second computing device. In one embodiment, a first computing device receives a read request and a volume identifier and a data identifier from a second computing device; accesses a cache to select the storage volume identified by the volume identifier; iteratively attempts to read data identified by the data identifier until a copy of the data is successfully read from a storage node belonging to the selected storage volume; and transmits the copy of the data to the second computing device.

Abstract: In one embodiment, a computer program product includes a computer readable storage medium having computer readable program code embodied therewith, configured for: validating a replication of copy services between a first storage system and a second storage system, removing a plurality of existing copy relationships between the first storage system and a failed storage system, creating a plurality of copy relationships between the first storage system and the second storage system, and synchronizing a plurality of data between the first storage system and the second storage system. In more embodiments, a system includes logic for performing the above functionality, and a method includes steps for performing the above functionality.

Abstract: A system and method for adaptive RAID geometries. A computer system comprises client computers and data storage arrays coupled to one another via a network. A data storage array utilizes solid-state drives and Flash memory cells for data storage. A storage controller within a data storage array is configured to determine a first RAID layout for use in storing data, and write a first RAID stripe to the device group according to the first RAID layout. In response to detecting a first condition, the controller is configured to determine a second RAID layout which is different from the first RAID layout, and write a second RAID stripe to the device group according to the second layout, whereby the device group concurrently stores data according to both the first RAID layout and the second RAID layout.

Abstract: Digital objects are stored and accessed within a fixed content storage cluster by using a page mapping table and a pages index. A stream is read from the cluster by using a portion of its unique identifier as a key into the page mapping table. The page mapping table indicates a node holding a pages index indicating where the stream is stored. A stream is written by storing the stream on any suitable node and then updating a pages index stored within the cluster responsible for knowing the location of digital objects having unique identifiers that fall within a particular address range. The cluster recovers from a node failure by first replicating streams from the failed node and reallocating a page mapping table to create a new pages index. The remaining nodes send records of the unique identifiers corresponding to objects they hold to the new pages index.

Abstract: An information processing apparatus includes: a dividing unit that divides a storage region in accordance with storage region management information, the storage region management information and type information; a setting unit that selects a first division region from division regions indicative of the divided storage region and that puts the first division region in a stand-by state; a detecting unit that detects an abnormality in information processing when the information processing is performed using a second division region of the division regions; a controlling unit that puts the second division region in the stand-by state and that causes the first division region, which has been in the stand-by state, to recover; and an analyzing unit that adds the second division region that is in the stand-by state to a physical address space, and that analyzes information stored in the second division region.

Abstract: In traditional journal based replication environments, the journal is lost on failover. However, example embodiments of the present invention overcome this and other deficiencies by preserving a journal in a symmetric continuous data protection environment. Therefore, example embodiments of the present invention provide a method, an apparatus, and a computer program production for preserving a journal in a symmetric continuous data protection environment. The method comprises maintaining a journal in a journal-based replication environment comprising a production volume at a production site and a replication volume at a replication site and, after detecting a failover event, symmetrically preserving the journal after failover.

Abstract: A method for operating a mirrored disk storage system, comprises a determiner component for determining a repair characteristic of a pair of mirrored disks, a comparator for comparing said repair characteristic of a first of said pair with said repair characteristic of a second of said pair, and a cancelling component for cancelling a repair action for said one of said first or said second of said pair that is not selected by said selector.

Abstract: Various embodiments for reducing communication between cluster nodes and optimizing failover processing in a distributed shared memory (DSM)-based application by at least one processor device are provided. In one embodiment, for a data structure operable on a DSM, a read-mostly portion is maintained in a single copy sharable between the cluster nodes while an updatable portion is maintained in multiple copies, each of the multiple copies dedicated to a single cluster node.

Abstract: Disclosed is a method and system for saving the copybacked data in a drive and continuing to rebuild on the same drive where the copy back was in progress when the online drive, where the copy back is not initiated, fails.

Abstract: Systems and methods to manage memory are provided. A particular method may include storing data in a primary memory that is in communication with a processor and storing in a mirrored data in a mirrored memory. The mirrored data may be compressed, and the mirrored memory may be in communication with the processor. A failure condition associated with the data of the primary memory may be detected. In response to the detected failure condition, the mirrored data in the mirrored memory may be accessed.

Abstract: A method, system, and computer program product for restoring blocks of data stored at a corrupted data site using two or more mirror sites. The method commences by receiving a trigger event from a component within an application server environment where the trigger event indicates detection of a corrupted data site. The trigger is classified into at least one of a plurality of trigger event types, which trigger event type signals further processing for retrieving from at least two mirror sites, a first stored data block and a second stored data block corresponding to the same logical block identifier from the first mirror site. The retrieved blocks are compared to determine a match value, and when the match value is greater than a confidence threshold, then writing good data to the corrupted data site before performing consistency checks on blocks in physical or logical proximity to the corrupted data site.

Abstract: A method and system of optimizing the performance, capacity and data redundancy in a storage system by defining the LBA range on each storage element managing that corresponding range (slice) on each device using a data protection method optimized for the performance and level of data protection required. The creation of such a storage array along with the replacement of failed elements and the expansion of the capacity through the addition of additional elements is managed is an automatic and transparent manner.

Abstract: The present invention is directed to a method and apparatus for storing and reconstructing data. In one embodiment of the present invention, both real-time (i.e., dynamic) information and static information are stored in a Digital Video Disk (DVD) to replicate or restore an information system. The dynamic and static information are considered trust-support data. The trust-support data provides a complete view of the information system. For example, the state of current transactions operating in the information system is part of the trust-support data. The trust-support data may include GUI information, timestamp information, network information, authentication information, generalized receipts, and specialized receipts.

Abstract: Server supervisor processes in the segment nodes of a database cluster afford transparent reset mechanisms to a fault tolerant service (FTS). FTS probes only primary segments as to their status unless a primary segment does not respond, in which case FTS will probe the mirror of that primary-mirror pair, and change the state of the mirror to primary if the primary is faulty. Only a primary segment to initiate a reset of its mirror segment and then resets itself. If a mirror segment fails, it shuts down and its corresponding primary segment will report the failure to FTS. Transient communication failures are addressed by retry logic on FTS probing, and not reported to FTS. Reset is not initiated by FTS and preserves the segment state in the absence of errors.

Abstract: To generate a checkpoint for a virtual machine (VM), first, while the VM is still running, a copy-on-write (COW) disk file is created pointing to a parent disk file that the VM is using. Next, the VM is stopped, the VM's memory is marked COW, the device state of the VM is saved to memory, the VM is switched to use the COW disk file, and the VM begins running again for substantially the remainder of the checkpoint generation. Next, the device state that was stored in memory and the unmodified VM memory pages are saved to a checkpoint file. Also, a copy may be made of the parent disk file for retention as part of the checkpoint, or the original parent disk file may be retained as part of the checkpoint. If a copy of the parent disk file was made, then the COW disk file may be committed to the original parent disk file.

Abstract: In a storage system which supports a redundant disk configuration, while securing fault tolerance, a longer drive access time as well as a drop in I/O throughput are prevented when a redundant data update, generated due to a data update, is mirrored in the drive. A controller for controlling data I/O to and from the drive updates first redundant data and block data of a corresponding data stripe in the disk drive in correspondence with an update of block data of the logical volume, and the controller updates second redundant data on the basis of a predetermined number of block data which belong to the same data stripe as the updated block data with different timing from the update of the block data.

Abstract: A system and method for power management of storage resources are disclosed. A method may include detecting an occurrence of an event associated with a storage resource disposed in an array of storage resources. The method may further include transitioning the storage resource into a specified power state in response to the detection of the occurrence of the event. A system may include a storage resource and a power management module communicatively coupled to the storage resource. The storage resource may be disposed in an array of storage resources. The power management module may be operable to detect an occurrence of an event associated with the storage resource, and may be operable to transition the storage resource into a specified power state in response to the detection of the occurrence of the event.

Abstract: A file directory system comprises a directory file, a directory address for the directory file, and a directory address failsafe mechanism. The directory file includes one or more directory entries and one or more corresponding addresses for the one or more directory entries. The directory address failsafe mechanism functions to dispersed storage error encode the directory address to produce a plurality of encoded components of the directory address and transmit the plurality of encoded components of the directory address to a plurality of agent modules.

Abstract: In one embodiment of the present description, a copy relationship is established between a storage location at a first site and a storage location at a second site in a data storage system, wherein a dynamically assignable bitmap preset to one of a plurality of different predetermined bit patterns is selected as a function of both the availability of the selected bitmap and the type of predetermined bit pattern identified for the selected bitmap. The selected bitmap may be assigned as an out-of-sync bitmap wherein updates to the storage location at one site, which are to be copied to the storage location at the other site, are indicated in the selected bitmap, and data writes being written to the storage location at the one site, are copied to the storage location at the other site, using the selected bitmap as an out-of-sync bitmap. Other aspects are described.

Abstract: In one embodiment, a method of storing data includes storing a first copy of data in a solid state memory and storing a second copy of the data in a hard disk drive memory substantially simultaneously with the storing the first copy. In another embodiment, a system for storing data includes a solid state memory, at least one hard disk drive memory, and a controller for controlling storage of data in the solid state memory and the hard disk drive memory. Other methods, systems, and computer program products are also described according to various embodiments.

Abstract: A method of caching data includes: A. mirroring data processed by a first storage processor and a second storage processor between a first memory device of the first storage processor and a second memory device of the second storage processor; B. each of the first storage processor and the second storage processor monitoring an availability of the other of the first storage processor and the second storage processor; C. copying data stored in the first memory device to a third memory device and mirroring data processed by the first storage processor between the first memory device and the third memory device when the second storage processor becomes unavailable to the first storage processor; and D. copying data from the first memory device to the second memory device and mirroring data processed by the first storage processor and the second storage processor between the first memory device and the second memory device when the second storage processor becomes available to the first storage processor.

Abstract: A method for optimizing cleaning of maps in FlashCopy cascades includes determining whether a target disk of a map contains data unavailable to a downstream disk from an upstream disk in a FlashCopy cascade and detect whether the downstream disk has a copy of the data. Additionally, the method includes copying the data from the target disk to the downstream disk, if the target disk of the map contains data unavailable to the downstream disk from the upstream disk and the downstream disk does not have the copy of the data. Furthermore, the method includes copying the data from the target disk to the downstream disk, if the target disk of the map does not contain data unavailable to the downstream disk from the upstream disk or the downstream disk does have the copy of the data. Moreover, the method includes removing the map from the FlashCopy cascade.

Abstract: System and method for automated page-based management in storage systems. The system includes host computers, file servers and a storage system having automated page-based management means. The storage system interface receives instructions to change the condition for decision for migration regarding particular parts or the whole volume. The host computer can control execution of the migration performed by the storage system by specifying areas or volumes with the condition via the interface. Highly optimized, appropriate data placement and data relocation in computer system can be achieved when the application, host computer or management computer can recognize or predict the usage of the data or files. The storage system having automated page-based management may include compression/decompression and a control method for the compression and decompression process.

Abstract: The storage system of the present invention is able to generate one virtual logical device from different logical devices which exist in each of the different storage control units and remote-copy all or part of the virtual logical device to another logical device. The same virtual identifier is set for a volume of the first storage unit and for a volume of the second storage unit. The path control unit of the host identifies a plurality of volumes which have the same virtual identifier as one virtual volume. A remote copy pair can also be set by a virtual volume and a volume of the third storage unit. The setting of the virtual volume and the setting of the remote copy can be performed by means of an instruction from the management server.