3246results about "Redundant hardware error correction" patented technology

The invention is a hierarchical backup system. The interconnected network computing devices are put into groups of backup cells. A backup cell has a manager software agent responsible maintaining and initiating a backup regime for the network computing devices in the backup cell. The backups are directed to backup devices within the backup cell. Several backup cells can be defined. A manager software agent for a particular cell may be placed into contact with the manager software agent of another cell, by which information about the cells may be passed back and forth. Additionally, one of the software agents may be given administrative control over another software agent with which it is in communication.

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.

A flash drive has increased endurance and longevity by reducing writes to flash. An Endurance Translation Layer (ETL) is created in a DRAM buffer and provides temporary storage to reduce flash wear. A Smart Storage Switch (SSS) controller assigns data-type bits when categorizing host accesses as paging files used by memory management, temporary files, File Allocation Table (FAT) and File Descriptor Block (FDB) entries, and user data files, using address ranges and file extensions read from FAT. Paging files and temporary files are never written to flash. Partial-page data is packed and sector mapped by sub-sector mapping tables that are pointed to by a unified mapping table that stores the data-type bits and pointers to data or tables in DRAM. Partial sectors are packed together to reduce DRAM usage and flash wear. A spare/swap area in DRAM reduces flash wear. Reference voltages are adjusted when error correction fails.

For disaster recovery of a file server at an active site, the files that define the user environment of the file server are replicated to a virtual server at a disaster recovery site. To switch over user access from the active site to the disaster recovery site, the disaster recovery system determines whether there are sufficient network interfaces and file system mounts at the disaster recovery site. If so, the required resources are reserved, and user access is switched over. If not, an operator is given a list of missing resources or discrepancies, and a choice of termination or forced failover. Interruptions during the failover can be avoided by maintaining a copy of user mappings and a copy of session information at the disaster recovery site, and keeping alive client-server connections and re-directing client requests from the active site to the disaster recovery site.

A system for connection failover using redirection includes a primary server comprising a primary connection failover driver (CFD), a shadow server comprising a shadow CFD, and a client. The primary and shadow servers and the client are coupled via a network. The primary server and the client are configured to cooperate to establish a network connection. The primary CFD is configured to redirect a first message packet, targeted for transmission to the client over the network connection, to the shadow server. The shadow CFD is configured to copy contents of the first message packet into a log, and forward the first message packet to the client after the contents have been copied.

System and method for enabling application server request failover. For each application server request to be performed by a client computer, a requesting thread may be operable to utilize a custom wire-level communication protocol. Request failure detection mechanisms may be built into the custom wire-level communication protocol so that a requesting thread detects a failed request much sooner than if the thread utilized a standard communication protocol and relied on the client computer operating system for notification of failed requests. After sending a request to an application server, a requesting thread may be operable to “sleep” and then periodically wake up to poll the application server computer to determine whether the request has failed. If the requesting thread receives a response from the application server computer indicating that the request is not currently being processed, then the requesting thread may re-send the request. Receiving no response to the poll message may indicate that the application server computer is offline, e.g., due to a failure. The requesting thread may redirect the request to another application server computer if necessary.

Systems and methods, including computer program products, providing high-availability in server systems. In one implementation, a server system is cluster of two or more autonomous server nodes, each running one or more virtual servers. When a node fails, its virtual servers are migrated to one or more other nodes. Connectivity between nodes and clients is based on virtual IP addresses, where each virtual server has one or more virtual IP addresses. Virtual servers can be assigned failover priorities, and, in failover, higher priority virtual servers can be migrated before lower priority ones. Load balancing can be provided by distributing virtual servers from a failed node to multiple different nodes. When a port within a node fails, the node can reassign virtual IP addresses from the failed port to other ports on the node until no good ports remain and only then migrate virtual servers to another node or nodes.

A data storage facility for transferring data from a data altering apparatus, such as a production data processing site to a remote data receiving site. The data storage facility includes a first data store for recording each change in the data generated by the data altering apparatus. A register set records each change on a track-by-track basis. A second data store has first and second operating modes. During a first operating mode the second data store becomes a mirror of the first data store. During a second operating mode the second data store ceases to act as a mirror and becomes a source for a transfer of data to the data receiving site. Only information that has been altered, i.e., specific tracks that have been altered, are transferred during successive operations in the second operating mode. Commands from the local production site initiate the transfers between the first and second operating modes.

Described herein are systems and methods for multiplexing pipelined data for backup operations. Various data streams are combined such as by multiplexing by a multiplexing module. The multiplexing module combines the data from the various data streams received by receiver module(s) into a single stream of chunks. The multiplexing module may combine data from multiple archive files into a single chunk. Additional modules perform other operations on the chunks of data to be transported such as encryption, compression, etc. The data chunks are transmitted via a transport channel to a receive pipeline that includes a second receiver module and other modules. The data chunks are then stored in a backup medium. The chunks are later retrieved and separated such as by demultiplexing for restoring to a client or for further storage as auxiliary copies of the separated data streams or archive files.

Mechanisms and techniques operate in a computerized device to perform backup and restore operations on data portions such that if a backup server already has a copy of the content of a data portion, no client computer systems need to transfer a copy of the data portion to the backup server, even if the data portion in those clients has a different name, location, or other attributes. A backup client produces an identification of a data portion stored within a first computerized device to be backed up. The backup client conveys, to a backup server, the identification of the data portion stored within the computerized device and receives, over the communications interface, a transfer indication from the backup server. The backup client determines if the transfer indication indicates that the backup server already contains a copy of the data portion identified by the identification, and if not, the backup client transfers a copy of the data portion from the local storage device to the backup server over the communications interface.

Described are techniques used in a computer system for handling data operations to storage devices. A switching fabric includes one or more fast paths for handling lightweight, common data operations and at least one control path for handling other data operations. A control path manages one or more fast paths. The fast path and the control path are utilized in mapping virtual to physical addresses using mapping tables. The mapping tables include an extent table of one or more entries corresponding to varying address ranges. The size of an extent may be changed dynamically in accordance with a corresponding state change of physical storage. The fast path may cache only portions of the extent table as needed in accordance with a caching technique. The fast path may cache a subset of the extent table stored within the control path. A set of primitives may be used in performing data operations. A locking mechanism is described for controlling access to data shared by the control paths.

Methods, apparatus and computer programs have been provided for mitigating a problem of non-optimal recovery from storage device failures. A method involves determining a required write performance for rebuilding data of a failed device, based at least partly on the potential read performance of storage devices in a data rebuild; and allocating a virtual storage area within available storage, which allocation of virtual storage is based at least partly on the required write performance. Data is rebuilt by writing to the allocated virtual storage area, and data recovery is completed by migrating this rebuilt data to at least one data storage device such as a spare physical storage device within the array.

A method or system for supporting a computer systems self repair, including the computer executed steps for booting from a first boot device, and booting from a second boot device in response to a signal indicating a need for repair. While booted from the second boot device the computer system is capable of repairing software on the first boot device. The signal may effect a logical or physical switch. Repairing software may be performed in part by copying BIOS, template, backup or archive software from a device other than the first boot device. Repairing software may be performed automatically without direction by a user or according to preset preferences.

In a nonvolatile memory with block management system that supports update blocks with non-sequential logical units, an index of the logical units in a non-sequential update block is buffered in RAM and stored periodically into the non-volatile memory. In one embodiment, the index is stored in a block dedicated for storing indices. In another embodiment, the index is stored in the update block itself. In yet another embodiment, the index is stored in the header of each logical unit. In another aspect, the logical units written after the last index update but before the next have their indexing information stored in the header of each logical unit. In this way, after a power outage, the location of recently written logical units can be determined without having to perform a scanning during initialization. In yet another aspect, a block is managed as partially sequential and partially non-sequential, directed to more than one logical subgroup.

A system and method for updating a replicated destination file system snapshot with changes in a source file system snapshot, facilitates construction of a new directory tree on the destination from source update information using a temporary or “purgatory” directory that allows any modified and deleted files on the destination active file system to be associated with (e.g. moved to) the purgatory directory if and until they are reused. In addition, an inode map is established on the destination that maps source inode numbers to destination inode numbers so as to facilitate building of the destination tree using inode/generation number tuples. The inode map allows resynchronization of the source file system to the destination. The inode map also allows association of two or more destination snapshots to each other based upon their respective maps with the source.

The present invention provides methods and systems for performing load balancing via a plurality of virtual servers upon a failover using metrics from a backup virtual server. The methods and systems described herein provide systems and methods for an appliance detecting that a first virtual server of a plurality of virtual servers having one or more backup virtual servers load balanced by an appliance is not available, identifying at least a first backup virtual server of a one or more backup virtual servers of the first virtual server is available, maintaining a status of the first virtual server as available in response to the identification, obtaining one or more metrics from the first backup virtual server of a one or more backup virtual servers, and determining the load across the plurality of virtual servers using the metrics obtained from the first backup virtual server associated with the first virtual server.

A system and a method for transparent takeover (or failover) of a remote client TCP connection from a first server in a cluster of interconnected servers to a second server provides the storing of shared state information relative to the connection on each involved server and using of the shared state information to reestablish the connection on the second server. A message using a sequence number to refer to a previously transmitted data element (such as a byte) is sent by the second server and a received client acknowledgement (ACK) of that sequence number, or a higher one, is used to synchronize the server's data packet transmission sequence number with the ACK-transmitted sequence number. If synchronization is successful, then the connection is restarted on the second server from the point of termination/failure on the first server.

A database management system ensures consistency between primary and mirrored backup copies of a database, despite occurrence of a suspending condition interrupting the normal process of mirroring the primary database. One or more primary controllers are provided, each having a data storage unit with multiple primary data storage devices. Multiple secondary controllers each have multiple associated secondary data storage devices, each secondary controller being coupled to one primary controller. One or more primary databases reside on the primary devices, with a corresponding number of secondary databases residing on the secondary devices. Each secondary database mirrors a corresponding primary database. Either a host, attached to a primary controller, or one of the primary controllers itself, maintains a map cross-referencing each primary and secondary database with the primary and secondary devices containing portions thereof. If a predefined "suspending condition" affecting data mirroring occurs, the host or primary controller consults its map to identify all primary and secondary devices affected by the condition. Then, each primary controller stops all ongoing and future read/writes with each of its affected primary devices. Each primary controller also directs each secondary controller having an affected secondary device to stop mirroring the primary databases stored on that device. Then, the primary controller starts intermediate change recording and resumes read/writes with its primary devices. When the suspending condition ends, each primary controller applies the appropriate logged changes to its secondary database(s) and then reactivates each secondary database.

A method for storing data in a fault-tolerant storage subsystem having an array of failure independent data storage units, by dividing the storage area on the storage units into a logical mirror area and a logical stripe area, such that when storing data in the mirror area, duplicating the data by keeping a duplicate copy of the data on a pair of storage units, and when storing data in the stripe area, storing data as stripes of blocks, including data blocks and associated error-correction blocks.

A disk drive system and method capable of dynamically allocating data is provided. The disk drive system may include a RAID subsystem having a pool of storage, for example a page pool of storage that maintains a free list of RAIDs, or a matrix of disk storage blocks that maintain a null list of RAIDs, and a disk manager having at least one disk storage system controller. The RAID subsystem and disk manager dynamically allocate data across the pool of storage and a plurality of disk drives based on RAID-to-disk mapping. The RAID subsystem and disk manager determine whether additional disk drives are required, and a notification is sent if the additional disk drives are required. Dynamic data allocation and data progression allow a user to acquire a disk drive later in time when it is needed. Dynamic data allocation also allows efficient data storage of snapshots/point-in-time copies of virtual volume pool of storage, instant data replay and data instant fusion for data backup, recovery etc., remote data storage, and data progression, etc.

In a computer system, the controller of one or more primary data recording devices sends update information to the controller of one or more secondary data recording devices to maintain a remote copy of data stored on the primary data recording devices. The primary controller receives a command from a computer that specifies a prospective suspend time after which remote copy operation is to be suspended. After the suspend time passes, the primary controller stops sending the update information to the secondary controller and begins storing indicators of the updated information in cache memory. The primary controller may resume remote copy operation in response to a command received from the computer by first entering into a pending mode of operation in which cached indicators are used to identify update information that must be sent to the secondary controller to resynchronize the remote copy. When the information for all cached indicators has been sent, normal remote copy operation may be resumed.

Two data centers located in the vicinity are connected using a synchronous transfer copy function, and one of the data centers is coupled with a third data center disposed at a remote location by an asynchronous remote copying function. The order whereat a storage sub-system located in the vicinity has received data from a host is consistently guaranteed, and the third data center holds the data. Further, each storage sub-system includes a function whereby, during normal operation, data can be exchanged and the data update state can be obtained by the storage sub-systems located in the two data centers that do not directly engage in data transmission.

Systems and methods are disclosed for storing the firmware and other data of a flash memory controller, such as using a RAID configuration across multiple flash memory devices or portions of a single memory device. In various embodiments, the firmware and other data used by a controller, and error correction information, such as parity information for RAID configuration, may be stored across multiple flash memory devices, multiple planes of a multi-plane flash memory device, or across multiple blocks or pages of a single flash memory device. The controller may detect the failure of a memory device or a portion thereof, and reconstruct the firmware and/or other data from the other memory devices or portions thereof.

A solid-state storage retention monitor determines whether user data in a solid-state device is in need of a scrubbing operation. One or more reference blocks may be programmed with a known data pattern, wherein the reference block(s) experiences substantially similar P/E cycling, storage temperature, storage time, and other conditions as the user blocks. The reference blocks may therefore effectively represent data retention properties of the user blocks and provide information regarding whether/when a data refreshing operation is needed.

A portion of a storage controller's cache memory is used as a virtual solid state disk storage device to improve overall storage subsystem performance. In a first embodiment, the virtual solid state disk storage device is a single virtual disk drive for storing controller based information. In the first embodiment, the virtual solid state disk is reserved for use by the controller. In a second embodiment, a hybrid virtual LUN is configured as one or more virtual solid state disks in conjunction with one or more physical disks and managed using RAID levels 1-6. Since the hybrid virtual LUN is in the cache memory of the controller, data access times are reduced and throughput is increased by reduction of the RAID write penalty. The hybrid virtual LUN provides write performance that is typical of RAID 0. In a third embodiment, a high-speed virtual LUN is configured as a plurality of virtual solid state disks and managed as an entire virtual RAID LUN. Standard battery backup and redundant controller features of RAID controller technology ensure virtual solid state disk storage device non-volatility and redundancy in the event of controller failures.

A cluster recovery process is implemented across a set of distributed archives, where each individual archive is a storage cluster of preferably symmetric nodes. Each node of a cluster typically executes an instance of an application that provides object-based storage of fixed content data and associated metadata. According to the storage method, an association or “link” between a first cluster and a second cluster is first established to facilitate replication. The first cluster is sometimes referred to as a “primary” whereas the “second” cluster is sometimes referred to as a “replica.” Once the link is made, the first cluster's fixed content data and metadata are then replicated from the first cluster to the second cluster, preferably in a continuous manner. Upon a failure of the first cluster, however, a failover operation occurs, and clients of the first cluster are redirected to the second cluster. Upon repair or replacement of the first cluster (a “restore”), the repaired or replaced first cluster resumes authority for servicing the clients of the first cluster. This restore operation preferably occurs in two stages: a “fast recovery” stage that involves preferably “bulk” transfer of the first cluster metadata, following by a “fail back” stage that involves the transfer of the fixed content data. Upon receipt of the metadata from the second cluster, the repaired or replaced first cluster resumes authority for the clients irrespective of whether the fail back stage has completed or even begun.

A non-volatile memory is constituted from a set of memory planes, each having its own set of read/write circuits so that the memory planes can operate in parallel. The memory is further organized into erasable blocks, each for storing a logical group of logical units of data. In updating a logical unit, all versions of a logical unit are maintained in the same plane as the original. Preferably, all versions of a logical unit are aligned within a plane so that they are all serviced by the same set of sensing circuits. In a subsequent garbage collection operation, the latest version of the logical unit need not be retrieved from a different plane or a different set of sensing circuits, otherwise resulting in reduced performance. In one embodiment, any gaps left after alignment are padded by copying latest versions of logical units in sequential order thereto.

A router and routing protocol redundancy are disclosed to reduce service outage or degradation for a network device and thus to increase service availability on a network due to software and hardware failures of the network device. A network device such as router includes a redundancy platform having an active controller system and a standby controller system. A routing protocol state change is received or generated by the active controller system. The received or generated routing protocol state change is replicated to the standby controller system. By replicating the routing protocol state change, the standby controller system can maintain the routing protocol sessions for the network device if a failure occurs in the active controller system. Furthermore, the routing protocol states are maintained in realtime to handle the dynamic changes created by routing protocols.

A system and method for data storage in an array. A system includes a client coupled to a storage subsystem including data storage locations addressable as rows and columns in an array. Each column comprises a separate storage device. Each row includes redundant data. For a given row, a coordinating storage device coordinates the computation and storage of redundant data. The system detects a failure of a storage region and in response, configures an overlay storage device to temporarily overlay the failed region, maintains an association between the overlay device and the failed region, and maintains a record of changes made to the overlay device while the region is in a failed state. In response to detecting that the failed region has been restored, the system uses the association to identify the overlay device and uses the record of changes made to the overlay device to resynchronize the failed region.

A system and method for improving the efficiency of the transmission of updated blocks generated by logging all the block allocations and deletes as well as CPs and PCPI creation and deletion in a persistent log. The log is scanned during each update cycle (in which changes are transmitted to a destination mirror) by the storage operating system, and only changed blocks that are referenced by the file system as it existed at the end of the update cycle or referenced by PCPIs that existed at the end of the update cycle are actually sent in the transmission. This reduces the number of changes being transmitted.