Abstract: A technique includes in a data storage device, sensing a plurality of data streams from a track of storage media as the media moves in a given direction using a plurality of read elements such that at least one of the read elements is redundant. The technique includes combining the data streams to generate a data stream indicating data read from the track.

Abstract: Example apparatus and methods provide improved reclamation, garbage collection (GC) and defragmentation (defrag) for data storage devices including solid state drives (SSD) or shingled magnetic recording (SMR) drives. An erasure code (EC) layer that facilitates logically or physically erasing data from the SSD or SMR as a comprehensive GC or defrag is added to the SSD or SMR. Erased data may be selectively recreated from the EC layer as needed. Pre-planned EC write zones may be established to further optimize GC and defrag. Recreated data may be written to selected locations to further optimize SSD and SMR performance. Erasure code data may be distributed to co-operating devices to further improve GC or defrag. Example apparatus and methods may also facilitate writing data to an SMR drive using tape or VTL applications or processes and providing a pseudo virtual tape library on the SMR drive.

Abstract: Example apparatus and methods monitor conditions in an object storage system. The conditions monitored may include a load balance measure in the system, a capacity balance measure in the system, a fault tolerance measure in the system, or a usage pattern measure in the system. A distribution plan or redistribution plan for storing or moving erasure codes in the object storage system may be determined based on the conditions. The distribution plan or the redistribution plan for the erasure codes may be updated dynamically in response to changing conditions in the object storage system. The distribution or redistribution may depend on a weighted combination of the load balance measure, the capacity balance measure, the fault tolerance measure, or the usage pattern measure so that responding to one sub-optimal condition (e.g., load imbalance) does not create a different sub-optimal condition (e.g., unacceptable fault tolerance).

Abstract: What is disclosed is a method of operating a volume access system. The method includes processing at least a first file to generate a file system view of the first file comprising a plurality of items within the first file, and providing the file system view of the first file over a network interface as a hierarchical data volume. The method also includes receiving an access request for a requested item of the hierarchical data volume over the network interface, and in response, providing access to a first item of the plurality of items within the first file corresponding to the requested item.

Abstract: Example apparatus and methods combine erasure coding with data deduplication to simultaneously reduce the overall redundancy in data while increasing the redundancy of unique data. In one embodiment, an efficient representation of a data set is produced by deduplication. The efficient representation reduces duplicate data in the data set. Redundancy is then added back into the data set using erasure coding. The redundancy that is added back in adds protection to the unique data associated with the efficient representation. How much redundancy is added back in and what type of redundancy is added back in may be controlled based on an attribute (e.g., value, reference count, symbol size, number of symbols) of the unique data. Decisions concerning how much and what type of redundancy to add back in may be adapted over time based, for example, on observations of the efficiency of the overall system.

Abstract: A method for converting metadata in a hierarchical configuration within a filesystem from a first format to a second format includes reading metadata in the first format within the hierarchical configuration; writing the metadata from the hierarchical configuration into a flat file; and writing the metadata back into the hierarchical configuration, the metadata being in the second format. The method can also include increasing the size of each of a first inode and a second inode within a first inode chunk in the filesystem, assigning the first inode to the first inode chunk, and assigning the second inode to a second inode chunk.

Abstract: Software, systems, and methods are disclosed herein for enhanced updating of replica storage volumes within virtual machine environments. A first group of data blocks of a plurality of data blocks on an underlying storage volume that have changed are identified. A second group of data blocks of the first group of data blocks that are live are identified. Changed data items associated with the second group of data blocks are identified. An ancillary process is initiated on the changed data items. An update of the replica of the target storage volume with the second group of data blocks is also initiated.

Abstract: Apparatus, methods, and other embodiments associated with object synthesis are described. One example apparatus includes logic for identifying a block in a data de-duplication repository and for identifying a reference to the block. The apparatus also includes logic for representing a source object using a first named, organized collection of references to blocks in the data de-duplication repository and logic for representing a target object using a second named, organized collection of references. The apparatus is configured to synthesize the target object from the source object. Since synthesis may be complicated by edge cases, the apparatus is configured to account for conditions including a block in the target object needing less than all the data in a source object block, data to be used to synthesize the target object residing in a sparse hole in a data stream, and the target object needing data not present in the source object.

Abstract: A storage media retrieval assembly (22) for moving storage media (16) within a media library (10) including a library housing (12), comprises a picker system (32), an assembly base (30), and a first sensor (240A). The picker system (32) selectively engages the storage media (16). The assembly base (30) supports the picker system (32). The assembly base (30) is movable relative to the library housing (12). The first sensor (240A) senses if the assembly base (30) is level relative to the library housing (12). Additionally, the retrieval assembly (22) can further comprise a mover (28) that is secured to the assembly base (30), the mover (28) selectively moving the assembly base (30) relative to the library housing (12). In alternative embodiments, the first sensor (240A) or a second sensor (238A) can be a home sensor that senses a home position of the mover (28) relative to the library housing (12).

Abstract: A retrieval assembly (22) for moving storage media (16) within a media library (10), the media library (10) including a rack assembly (20) having a first rack (20A) and a spaced apart second rack (20B), comprises a picker system (32), an assembly base (30), a first mover (28A), a second mover (28B), and a control system (26). The picker system (32) selectively engages the storage media (16). The assembly base (30) supports the picker system (32). The first mover (28A) is secured to the assembly base (30), and selectively moves along the first rack (20A). The second mover (28B) is also secured to the assembly base (30), and selectively moves along the second rack (20B). The second mover (28B) is spaced apart from the first mover (28A). The control system (26) controls independent movement of the first mover (28A) and the second mover (28B) to position the assembly base (30) relative to the storage media (16).

Abstract: Embodiments disclosed herein provide magnetic media access heads with metal coatings. In a particular embodiment, a magnetic media head for accessing magnetic media comprises a base substrate configured to support a magnetic head layer. The magnetic head layer is formed on the base substrate and configured to magnetically access the magnetic media. A metallic layer formed over the magnetic head layer and disposed between the magnetic head layer and the magnetic media when the magnetic media is positioned for access by the magnetic head layer.

Abstract: Example apparatus and methods concern storing additional information about inodes to facilitate n-way inode translation between local inode spaces and external inode spaces. Example apparatus and methods also concern publishing information about actions that affect inodes to facilitate n-way inode translation. Additional data is added to local file systems so that a local file system can determine whether an inode for which an action is requested or reported is a native inode or an imported inode. The additional data added to the local file systems through the updated inode data storage and inode action publication also facilitates determining which local inode to act on based on the n-way inode translation mechanism.

Abstract: Example apparatus and methods monitor conditions in a tiered storage system. The conditions monitored may include the availability of different numbers and types of devices including an erasure code based object storage system. The conditions monitored may also include the availability and type of devices available to the erasure code based object storage system. A redundancy policy for storing an item using the erasure code based object storage system may be determined based on the conditions. Erasure codes associated with the item may then be stored in the erasure code based object storage system as controlled, at least in part, by the redundancy policy. The redundancy policy for the erasure codes may be updated dynamically in response to changing conditions on the tiered storage system.

Abstract: Example apparatus and methods distribute ranges or erasure codes associated with ranges to reduce or minimize the impact of a single point of failure in an object store. Erasure codes associated with related ranges to be stored in an object store may be accessed and selectively distributed to different storage devices associated with the object store. The erasure codes may be distributed according to a distribution plan so that an unavailability of one storage device will cause less than all of the related ranges to become unavailable. Example apparatus and methods may also provide a partial GET operation that will retrieve erasure codes associated with less than an entire object or with less than all possible ranges for an object. The partial GET operation may facilitate reconstructing less than an entire object, which may be valuable in, for example, weblog analytics.

Abstract: An example method includes determining a configuration of two or more partitions for a sequential access medium. At least one partition stores data de-duplication data structures while at least one other partition stores a repository of unique data blocks associated with the data structures. The method also includes controlling a data de-duplication computer to configure the sequential access medium according to the configuration. The method includes producing an output sequence for writing the data structures and a set of unique data blocks associated with the set of data structures to the sequential access medium as configured with the two or more partitions. One embodiment includes controlling a data de-duplication computer to write the data de-duplication data structures and the set of unique data blocks to the sequential access medium according to the output sequence.

Abstract: Example apparatus and methods process virtual machine image level backups that may include files that are compressed and files that are not compressed. Example apparatus and methods may produce virtual machine image level backups by selectively compressing some files associated with the image while leaving other files in their uncompressed state. Example apparatus and methods may selectively recover a file or even an entire disk image from an image level backup that may include both compressed files and files that are not compressed. The file recovery or image recovery may be performed at the file level by accessing files in the image and selectively decompressing files that are compressed in the image while passing through files that are not compressed in the image. Different files in a single image may be compressed or decompressed using different techniques.

Abstract: A replica control system includes software to control replication in virtual environments. The replica control system identifies a plurality of data blocks within an underlying storage volume in response to a request to update a replica of a target storage volume, identifies changed data blocks of the plurality of data blocks within the underlying storage volume, and identifies a subset of the changed data blocks with which to update the replica of the target storage volume based on a characteristic of the changed data blocks.

Abstract: Example apparatus and methods use two types of storage to improve boot time associated with recovering a virtual machine running on a hypervisor. The first storage is deduplication based and the second storage is not deduplication based. Example apparatus and methods may read data from the first storage to support operations immediately upon the VM booting and until a full recovery has been completed. Example apparatus and methods may also write a snapshot to the second storage and then support random input/output for the virtual machine from the snapshot in the second storage immediately upon the VM booting until a full recovery has been completed. Having dual devices facilitates using deduplication storage for deduplication-centric I/O while non-deduplication storage is used for random I/O while transfer of a recovery image from a backup device to a primary device associated with the VM is completed.

Abstract: Embodiments disclosed herein provide systems and method for storing metadata to unused portions of a virtual disk file. In a particular embodiment, a method provides selecting a virtual disk file stored on a data storage volume and identifying unused portions of the virtual disk file. The method further provides writing metadata for the virtual disk file in the unused portions of the virtual disk file.

Abstract: Example apparatus and methods combine erasure coding with data deduplication to simultaneously reduce the overall redundancy in data while increasing the redundancy of unique data. In one embodiment, an efficient representation of a data set is produced by deduplication. The efficient representation reduces duplicate data in the data set. Redundancy is then added back into the data set using erasure coding. The redundancy that is added back in adds protection to the unique data associated with the efficient representation. How much redundancy is added back in and what type of redundancy is added back in may be controlled based on an attribute (e.g., value, reference count, symbol size, number of symbols) of the unique data. Decisions concerning how much and what type of redundancy to add back in may be adapted over time based, for example, on observations of the efficiency of the overall system.