Abstract: Described are techniques for selecting a storage pool configuration. A set of one or more candidate storage pool configurations is determined. For each of the candidate storage pool configurations of the set, a reliability calculation is performed to determine a reliability value indicating reliability of the candidate storage pool configuration. For each of the candidate storage pool configurations of the set, an availability calculation is performed to determine an availability value indicating availability of the candidate storage pool configuration. In accordance with selection criteria, one of the candidate storage pool configurations of the set for a first storage pool is selected. The selection criteria includes the availability value and the reliability value for each of the plurality of candidate storage pool configurations.

Abstract: A storage system includes a first control apparatus; at least one second control apparatus managed by the first control apparatus; and a storage unit accessed by the second control apparatus. The second control apparatus determines based on detection of an error of an input/output process for storage in the storage unit whether the storage is in a blocking state, executes a resumption process of the input/output process when the storage is in the blocking state, judges whether an error occurrence frequency of the input/output process is at least a predetermined value, when the storage is not in the blocking state, and transmits to the first control apparatus, a blocking process request for the storage, when the error occurrence frequency is at least the predetermined value. The first control apparatus executes a blocking process and an error process of the storage, based on reception of the blocking process request.

Abstract: 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.

Abstract: Disclosed is a system and method for providing data integrity for pinned cache even if a RAID controller card fails while it has pinned cache or a memory module goes bad. A controller is enabled to use complete cache lines even if pinned cache is present, thereby enabling other virtual disks to run in write-back mode when pinned cache is present.

Abstract: A method begins by storage units of a dispersed storage network (DSN) receiving a set of encoded data slices for storage. The method continues with a first storage unit determining whether to store a first encoded data slice as a first set of encoded data sub-slices. The method continues with the first storage unit encoding the first encoded data slice in accordance with a first dispersed storage error encoding function to produce the first set of encoded data sub-slices. The method continues by a second storage unit of the storage units determining whether to store a second encoded data slice as a second set of encoded data sub-slices. The method continues with the second storage unit encoding the second encoded data slice in accordance with a second dispersed storage error encoding function to produce the second set of encoded data sub-slices.

Abstract: A method and system for are provided for error detection in a mirrored data storage system. The method includes a first mirrored system applying a first error correction code (ECC) algorithm and a second mirrored system applying a second error correction code algorithm. The method reads recovered data in each of the first and second mirrored systems and processes the recovered data in each of the first and second mirrored systems by applying both first and second error correction code algorithms to produce four calculated error correction code values. The method uses the calculated error correction code values to determine the correct recovered data of the first and second mirrored systems.

Abstract: A computer-implemented method for projecting hierarchical storage management functions may include enumerating objects stored on an endpoint system via an agent on the endpoint system. The computer-implemented method may also include transmitting, via a web service, information relating to the enumeration to a server. The computer-implemented method may further include receiving, via the web service, a hierarchical storage management policy from the server. The computer-implemented method may additionally include enacting the hierarchical storage management policy via the agent. Various other methods and systems are also disclosed.

Abstract: A storage control device includes a processor. The processor is configured to monitor driving states of each of a plurality of storage drives included in a storage device. The processor is configured to rearrange data stored in the storage drives so that the driving states of the storage drives are uniformed.

Abstract: A method for managing storage devices in a storage subsystem having an array of storage devices, according to one embodiment, includes determining that a storage device in an array of storage devices has failed. A first candidate storage device having storage device characteristics that match storage device characteristics of the failed storage device is identified. The first candidate storage device is exchanged with a second candidate storage device in response to determining that the second candidate storage device has storage device characteristics that are more similar to the storage device characteristics of the array of storage devices than the first candidate storage device.

Abstract: A method begins by determining that a disk drive of a slice server has been replaced with a new disk drive. The method continues by identifying a data slice that was stored on the disk drive and identifying a data segment based on the identified data slice. The method continues by identifying other slice servers that are storing other data slices of the encoded data segment. The method continues by retrieving, from the other slice servers, a sufficient number of the other data slices to reconstruct the data segment and decoding the sufficient number of the other data slices to reconstruct the data segment. The method continues by encoding the reconstructed data segment in accordance with the information dispersal algorithm to produce a new set of data slices. The method continues by selecting a data slice of the new set of data slices as a rebuilt data slice.

Abstract: Methods, apparatus and computer program products implement embodiments of the present invention that enable digital information devices having respective storage devices and memories to distributedly store, for a logical volume, data and first and second parity values across corresponding regions of the storage devices. Freezers having a one-to-one correspondence with the storage devices are distributedly stored in the memories. Upon detecting, in a cache, updated data for one or more first regions on the storage devices, existing data from the one or more first regions, and additional data for parity calculations are retrieved from one or more corresponding second regions on the storage devices, and first and the second parity values are calculated using the updated data, the existing data and the additional data. The updated data and the calculated first and second parity values are stored to the freezers, and then destaged from the freezers to the storage devices.

Abstract: A data processing module includes a first interface connected to (i) a host via a second interface, and (ii) storage arrays. The first interface receives, from the host via the second interface, blocks of data for storage in one or more of the storage arrays. A memory stores the blocks of data received by the first interface. A processor (i) determines error checking and correcting processing to be applied to each block of data of the blocks of data, and (ii) for each block of data, (a) transfers the block of data from the memory to a selected storage array of the storage arrays, and (b) assigns, to the selected storage array, the error checking and correcting processing to be applied to the block of data. The memory stores a map. The map indicates storage of the blocks of data among the storage arrays.

Abstract: A distributed data storage method, apparatus, and system for reducing a data loss that may result from a single-point failure. The method includes: splitting a data file to generate K data slices, splitting each data slice of the K data slices to generate M data blocks for each data slice, and performing check coding on the M data blocks by using a redundancy algorithm to generate N check blocks; determining, by using a random algorithm, a first physical storage node corresponding to one block of the M data blocks and the N check blocks, and determining at least M+1 different physical storage nodes based on the determined first physical storage node and according to a first rule-based sorting manner; and storing at least M+1 blocks of the M data blocks and the N check blocks onto the at least M+1 different storage nodes, where K, M, and N are integers.

Abstract: According to one embodiment, a drive array apparatus includes a plurality of data storage drives constituting a drive array and a controller. The controller divides all data storage areas of each of the data storage drives into a plurality of logical unit areas and associates and manages each of the logical unit areas and each of the data storage drives. The controller identifies a logical unit area of an error occurrence object based on a notification from a data storage drive where an error occurred, restores data of the identified logical unit area, and performs reconfiguration processing of the drive array.

Abstract: A storage control device includes a processor. The processor is configured to request a plurality of disk devices storing data therein to notify the processor of degradation information on degradation of data stored in the respective disk devices. The processor is configured to instruct, based on first information among notified degradation information, the plurality of disk devices to rewrite data. The first information serves as a trigger of rewriting data. The first information is notified by at least one of the plurality of disk devices.

Abstract: A method for execution by a storage unit in a directory-less distributed storage network (DSN) begins by receiving a read request regarding a data segment of data. The method continues by determining, based on the read request, whether an encoded data slice of a set of encoded data slices is locally stored, wherein the data segment was dispersed storage error encoded to produce the set of encoded data slices. When the encoded data slices are locally stored, the method continues by generating a read response. The method continues by determining whether to forward the read request to another storage unit of the directory-less DSN. When the read request is to be forwarded, the method continues by identifying one or more storage units to which the read request is to be forwarded and the read request is then forwarded to the one or more identified storage units.

Abstract: Embodiments of the present invention provide a method and apparatus for reconstructing a RAID, and a system, when a first physical disk is faulty, finding DUs of other physical disks, where the DUs are located on a same LDS as a DU of the first physical disk, in each logic module of a pre-generated layout template, performing exclusive-OR on data read from the DUs of other physical disks, and writing the data into a hot spare DU of a second physical disk; and in the layout template, replacing a DU identifier of the first physical disk with a DU identifier of the second physical disk, where DUs corresponding to DU identifiers in each LDS in the layout template belong to different physical disks. The present invention can reduce time needed for writing the data, shorten time needed for RAID reconstruction and restoration, and improve a reconstruction speed.

Abstract: Disclosed is a system and method for providing data integrity for pinned cache even if a RAID controller card fails while it has pinned cache or a memory module goes bad. A controller is enabled to use complete cache lines even if pinned cache is present, thereby enabling other virtual disks to run in write-back mode when pinned cache is present.

Abstract: A method and system for rebuilding data following a disk failure within a RAID storage system. The rebuild process keeps track of the relative number of READ operations across a RAID group so that following a RAID disk failure, the most frequently read areas of the RAID group can be rebuilt before less frequently accessed areas. Host READs to the rebuilt area will no longer necessitate on-the-fly rebuild from parity data, and thus host performance will be much less impacted than with prior rebuild processes.

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: In one aspect, a method includes forming a virtualized grid consistency group to replicate a logical unit, running a first grid copy on a first data protection appliance (DPA) replicating a first portion of the logical unit, running a second grid copy on a second DPA replicating a second portion of the logical unit, sending IOs to the first DPA if the IOs are to a first set of offsets and sending IOs to the second DPA if the IOs are to a second set of offsets.

Abstract: In one embodiment, a clustered storage system is configured to reduce parity overhead of Redundant Array of Independent Disks (RAID) groups, as well as to facilitate distribution and servicing of the storage containers among storage systems (nodes) of the cluster. The storage containers may be stored on one or more storage arrays of storage devices, such as solid state drives (SSDs), connected to the nodes of the cluster. The RAID groups may be formed from slices (i.e., portions) of storage spaces of the SSDs instead of the entire storage spaces of the SSDs. That is, each RAID group may be formed “horizontally” across a set of SSDs as slices (i.e., one slice of storage space from each SSD in the set). Accordingly, a plurality of RAID groups may co-exist (i.e., be stacked) on the same set of SSDs.

Abstract: A fault-tolerant configuration to share computer accessible data storage devices contained in a computer system with other such computer systems. Embodiments of the present invention allow sharing data storage devices contained in a first computer storage system with a second computer system by providing two or more independent connections to the data storage devices, such connections to the second computer system being independent of a motherboard (or a component thereon) contained in the first computer system, and thus ensuring continued access to the storage devices in the presence of component failures of the first computer system, such components being redundant.

Abstract: A method for managing storage devices in a storage subsystem having an array of storage devices includes receiving an error message; determining that the error message indicates that at least one storage device in the array of storage devices has failed; collecting an array record comprising storage device characteristics of the failed storage device in response to determining that the error message indicates that at least one storage device has failed; collating a candidate record comprising a plurality of candidate entries; comparing storage device characteristics of the failed storage device of the array record with the storage device characteristics of each of the candidate entries; identifying a first candidate storage device having storage device characteristics that match the storage device characteristics of the failed storage device; and identifying a second candidate storage device having storage device characteristics most similar to the storage device characteristics of the failed storage device.

Abstract: A method begins by first and second client devices transmitting first and second sets of write requests to storage units. The method continues with a storage unit sending a write response message to the first and second client devices, where the write response message indicates a storage unit score value for one of the client devices. The method continues with the first and second client devices interpreting the storage unit score values from the storage units to determine which client device has write priority. The method continues with the client device that has the write priority sending a set of next-phase write requests to the storage units. The method continues with the other client device that does not have the write priority sending a set of rollback requests to the storage units.

Abstract: Exemplary embodiments of the present invention disclose a method and system for reducing a probability of generating an unrecoverable error on a disk array during a disk rebuild. In a step, an exemplary embodiment identifies a disk to be replaced in the disk array, the disk array including a spare disk. In another step, an exemplary embodiment locates a region in the disk array that incurs a high number of reads and writes during a period prior to replacing the disk in the disk array. In another step, an exemplary embodiment scrubs data in a region in the disk array that has incurred a high number of accesses. In another step, an exemplary embodiment replaces the disk identified to be replaced with the spare disk in the disk array. In another step, an exemplary embodiment rebuilds data on the replaced disk on the spare disk in the disk array.

Abstract: A storage integrity system in a dispersed storage network scans an address range of data slices to identify errors in one of a plurality of encoded data slices, wherein the plurality of encoded data slices are generated from a data segment using an error encoding dispersal function. When the storage integrity system detects an error, it identifies one of the encoded data slices for rebuilding. The identified data slice is rebuilt in response to the type of error. For example, when the type of the error includes a temporary error, the storage integrity system waits a predetermined time period to determine whether the error still exists prior to rebuilding the identified data slice.

Abstract: Methods and systems for two device failure tolerance in a RAID 5 storage system. Features and aspects hereof provide for allocating a spare storage device in the storage system for use with a standard RAID level 5 storage volume to form an enhanced RAID level 5 volume. Additional redundancy information is generated and stored on the spare storage device such that the enhanced RAID level 5 volume is operated by the storage controller so as to survive a failure of up to two of the storage devices of the enhanced volume. The allocated spare storage device may be reallocated by the storage controller for another purpose in which case the storage controller continues to operate the enhanced volume as a standard RAID level 5 volume that can only tolerate a single failure of a storage device of the volume.

Abstract: Methods and apparatus for improved building of a hot spare storage device in a RAID storage system while avoiding reading of stale data from a failed storage device. In the recovery mode of the failed device, all data is write protected on the failed device. A RAID storage controller may copy as much readable data as possible from the failed device to the hot spare storage device. Unreadable data may be rebuilt using redundant information of the logical volume. Write requests directed to the failed device cause the addressed logical block address (LBA) to be marked as storing stale data. When a read request is directed to such a marked LBA, the read request returns an error status from the failed device to indicate that the data is stale. The RAID controller then rebuilds the now stale data for that LBA from redundant information of the logical volume.

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: By placing an encryption function below a RAID function and requiring independence of encryption functionality along the same boundaries of data member independence of the RAID function, failures of the encryption and key management for individual encryption functions can be recovered with the same data rebuild mechanism as the RAID function. For example, in a RAID set of disk drives, each data partition and each parity partition has a respective data encryption key for storing encrypted data or encrypted parity in the partition, and a LUN or logical volume is mapped to a stripe of data partitions and an associated parity partition across the RAID set so that the data rebuild mechanism of the RAID function may recover from a loss of a single data encryption key without compromising security of the LUN or logical volume.

Abstract: A disk array memory system comprises: a plurality of disks in a disk array for storage of content data and parity data in stripes, content data in a same stripe sharing parity bits of said parity data, each disk having a spare disk capacity including at least some of a predefined array spare capacity, said array spare capacity providing a dynamic space reserve over said array to permit data recovery following a disk failure event; a cache for caching content data prior to writing to said disk array; and a controller configured to select a stripe currently having a largest spare stripe capacity, for a current write operation of data from said cache, thereby to write all said data of said current write operation on a same stripe, thereby to maximize sharing of parity bits per write operation and minimize separate parity write operations.

Abstract: Various embodiments include apparatus and methods to store data in a first semiconductor memory unit and to store error correction information in a second semiconductor memory unit to recover the data. The error correction information has a value equal to at least the value of the data store in the first memory unit.

Abstract: The present disclosure includes methods and devices for stripe-based memory operation. One method embodiment includes writing data in a first stripe across a storage volume of a plurality of memory devices. A portion of the first stripe is updated by writing updated data in a portion of a second stripe across the storage volume of the plurality of memory devices. The portion of the first stripe is invalidated. The invalid portion of the first stripe and a remainder of the first stripe are maintained until the first stripe is reclaimed. Other methods and devices are also disclosed.

Abstract: A method is used in managing drive problems in data storage systems. It is determined, by a physical drive object, whether an I/O with a drive is able to be retried by another object. An overall retry time for the I/O is tracked. If the overall retry time is excessive, the drive is taken offline.

Abstract: A method of managing a distributed storage space. The method comprises mapping a plurality of replica sets to a plurality of storage managing modules installed in a plurality of computing units, each of the plurality of storage managing modules manages access of at least one storage consumer application to replica data of at least one replica of a replica set from the plurality of replica sets, the replica data is stored in at least one drive of a respective the computing unit, allocating at least one time based credit to at least one of each storage managing module and the replica data, iteratively renewing the time based credit as long a failure of at least one of the storage managing module, and the at least one drive and the replica data is not detected plurality of storage managing.

Abstract: A method begins by a dispersed storage (DS) processing module receiving data for storage in a dispersed storage network (DSN) memory and ascertaining dispersed storage error encoding parameters for encoding the data. The method continues with the DS processing module ascertaining storage units of the DSN memory for the storing an encoded version of the data and ascertaining a storage mapping that maps encoded data slices to storage units for storing the encoded version of the data. The method continues with the DS processing module encoding the data in accordance with the dispersed storage error encoding parameters to produce sets of encoded data slices. The method continues with the DS processing module generating a plurality of write requests for storing, in accordance with the storage mapping, encoded data slices of the sets of encoded data slices in a pattern across the storage units.

Abstract: The invention relates to a method and a system for regenerating a failed storage node from one or more storage nodes storing an original file and also reconstructing the said original file. The method involves encoding the file segments using a XOR operation, decoding the encoded file segment using the XOR operation and regenerating the failed node by using the storage nodes which are in active position. The regenerated file segments are further written to a new storage node.

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: Exemplary embodiments of the invention provide a distribution design for fast RAID rebuild architecture that avoids the deterioration of the availability/reliability in the distribution architecture. According to one aspect of the invention, a storage system comprises: a data storage unit including a plurality of storage devices; a storage controller including a processor, a memory, and a controller for controlling data transfer between the memory and corresponding storage devices in the data storage unit; and an internal network coupled between the storage controller and the storage devices. Based on loads of the processor of the storage controller and the internal network, the storage controller controls to limit a number of redundant storage devices over which to distribute a write data.

Abstract: A method begins by a processing module obtaining common storage name information regarding data that is stored in storage units of a distributed storage network (DSN) as a set of data slices. Each data slice of the set of data slices has a unique storage name, where each of the unique storage names for the set of data slices has common naming information regarding the data. The method continues where the processing module interprets the common storage name information to determine whether a difference exists between the common naming information of a data slice of the set of data slices and the common naming information of other data slices of the set of data slices. When the difference exists, the method continues where the processing module indicates a potential storage error of the data slice and implements a storage error process regarding the potential storage error of the data slice.

Abstract: The present invention is directed to a method for completing a stripe write operation in a timely fashion to a RAID drive pool which includes an abnormally slow drive. For example, the stripe write operation either completes within a required time interval, or an error is provided to the host/initiator which provides an indication to an application that the stripe write operation did not complete.

Abstract: A data storage method for a plurality of RAID systems includes an SAS expander recording information of failure of a disk of a plurality of RAID systems when failure of the disk is detected and reporting the information of failure of the disk to the RAID system server when the RAID system server sends a polling message to the SAS expander or tries accessing the failed disk. In response to the failure information of the failed disk from the SAS expander, the RAID system server sends a command to the SAS expander, to replace the disk with a hot spare disk.

Abstract: A storage-apparatus has a plurality of storage-devices and a controller for controlling data read from and write to the plurality of storage-devices, the controller includes a determination-unit and a restore-processing-unit, when a new storage-device has failed in a non-redundant state being a redundant group state without redundancy, in which some of the storage-devices had failed out of the plurality of storage-devices, the determination-unit configured to determine whether execution of compulsory restore of the redundant group is possible or not on the basis of a failure cause of the plurality of failed storage-devices, and if the determination unit determines that the execution of compulsory restore of the redundant group is possible, the restore-processing-unit configured to incorporate a plurality of storage-devices including a newly failed storage-device in the non-redundant state into the redundant group and to compulsorily restore the storage-apparatus to an available state.

Abstract: In a method for managing serial attached small computer system interface (SAS) expanders using a host computer, the host computer connects to an SAS expander storage system through a redundant array of independent disks (RAID) card. The SAS expander storage system includes a first switch device, a first SAS expander, a second SAS expander, a second switch, a flash memory, and hard disk drives. The method controls the first switch device to switch the RAID card from the first SAS expander to the second SAS expander when the first SAS expander fails to function, controls the second switch device to switch the flash memory from the first SAS expander to the second SAS expander, and controls the first switch device to connect each of the hard disk drives to the second SAS expander.

Abstract: The present disclosure is a system and method for improved RAID rebuilds under host IO conditions, that greatly improves rebuild times and prevents host IO starvation. A queue in a drive that is part of the RAID is used to store rebuild and host IO requests, with rebuild IOs issued to the head of the drive queue. Rebuild requests in the drive are delayed by a delay time. This delay ensures there is no unintended side effect of this invention that may result in host IO starvation for the RAID system. Delay is computed as a heuristic function from a plurality of variables, such as disk head response times, time allotted for rebuild, number of rebuild threads, drive behavior, rebuild IO profile, host IO profile including workload and locality, and a timeline of sequenced events, which in one preferred embodiment cycles every 70 seconds.

Abstract: Systems and methods for providing additional instructions for supporting efficient memory corruption detection in a processor. A physical memory may be a DRAM with a spare bank of memory reserved for a hardware failover mechanism. Version numbers associated with data structures allocated in the memory may be generated so that version numbers of adjacent data structures are different. A processor determines that a fetched instruction is a memory access instruction corresponding to a first data structure within the memory. For instructions that are not a version update instruction, the processor compares the first version number and second version number stored in a location in the memory indicated by the generated address and flags an error if there is a mismatch. For version update instructions, the processor performs a memory access operation on the second version number with no comparison check.

Abstract: A technique for operating a storage area network includes detecting an input/output operation failure associated with a logical unit number, which is associated with a first target port. The technique also includes determining, subsequent to the detected input/output operation failure, whether the logical unit number is associated with a second target port. Finally, the technique includes routing subsequent input/output operations for the logical unit number to the logical unit number via the second target port, in response to determining that the logical unit number is associated with the second target port.

Abstract: As apparatus and associated method for a dual active-active array storage system with a first controller with top level control of a first memory space and a second controller with top level control of a second memory space different than the first memory space. A seek manager residing in only one of the controllers defines individual command profiles derived from a combined list of data transfer requests from both controllers. A policy engine continuously collects qualitative information about a network load to both controllers to dynamically characterize the load, and governs the seek manager to continuously correlate each command profile in relation to the load characterization.

Abstract: In a computer system supporting execution of virtualization software and at least one instance of virtual system hardware, an interface is provided into the virtualization software to allow a program to directly define the access characteristics of its program data stored in physical memory. The technique includes providing data identifying memory pages and their access characteristics to the virtualization software which then derives the memory access characteristics from the specified data. Optionally, the program may also specify a pre-defined function to be performed upon the occurrence of a fault associated with access to an identified memory page. In this manner, programs operating both internal and external to the virtualization software can protect his memory pages, without intermediation by the operating system software.