Abstract: A computer-implemented method is provided for managing digital datasets stored on a multi-tiered storage system that includes several tiers of storage, the datasets likely to be accessed by one or more applications interacting with the storage system. The method includes monitoring an access history of datasets accessed by the one or more applications; and while monitoring the access history: computing probabilities of access, by the one or more applications, of the datasets stored on the storage system according to metadata associated to given datasets as identified in the monitored access history; and based on the computed probabilities of access, selecting one or more of the datasets to be moved across the tiers. Related storage systems and computer program products are also provided.

Abstract: An embodiment is directed to a method for determining an assignment of data to be stored on at least one storage tier i of a plurality of storage tiers of a tiered storage system. The method including, for the at least one storage tier i, steps of accessing storage device characteristics of the at least one storage tier i of the plurality; based on the accessed storage device characteristics, splitting the at least one storage tier i into Ni storage subtiers of the at least one storage tier i, the Ni storage subtiers having respective storage device characteristics; and based on characteristics of data to be stored on the tiered storage system and the respective storage device characteristics of the Ni storage subtiers, determining an assignment of data to be stored on each of the Ni storage subtiers. Embodiments are directed to related methods, systems and computer program products.

Abstract: Embodiments include methods for operating a first storage system having a first number of data storage drives for enabling access to a first set of removable media. Aspects include providing a second storage system having a number K of data storage drives for enabling access to a second set of removable media and providing a set of parameters describing operational characteristics of the second storage system. Aspects also include determining an analytical model using the set of parameters, the analytical model describing the variation of average waiting time as a function of system load over a predefined range covering multiple system load regime domains and determining values of the set of parameters using the analytical model and data of the second storage system. Aspects further include using the analytical model and the values of the set of parameters for reconfiguring the first storage system.

Abstract: A storage system is proposed which comprises a data storage device including a number N of removable storage media for storing data, with N?2, and a number m of drives, with m?1, wherein each of the m drives is configured to drive one of the removable storage media mounted to the drive. The storage system includes a server being coupled to the data storage device and configured to serve requests from clients, and a controller which is configured to control the data storage device to adaptively unmount the removable storage media based on a monitoring information of the requests at the data storage device, states of the drives, and states of the removable storage media.

Abstract: A method is provided for increasing data storage reliability in a heterogeneous storage system including multiple storage devices of different types. The devices store respective data subsets of a dataset. The method includes accessing configuration parameters for the dataset including first and second amounts of the data subsets respectively stored on the multiple storage devices. The method further includes estimating an initial global reliability of the heterogeneous storage system for the dataset, based on the configuration parameters. The method also includes determining an increased global reliability of the storage system for the dataset, by estimating a global reliability as would be obtained by modifying at least some of the configuration parameters, whereby at least the first and second amounts of the data subsets respectively stored on the devices are modified.

Abstract: A computing device writes data across storage devices in an erasure-coded system. The computing device computes data blocks and parity blocks from data and computes a portion of the data to be stored in the system. The computing is performed by one or more controllers included in a redundant array of an independent disks controller. The computing device provides the locations of the data blocks and the parity blocks in storage devices of an erasure-coded system. The location is determined using one or more placement nodes. The placement nodes are configured for managing placement schemes of data blocks and parity blocks on the storage devices.

Abstract: A storage system is proposed which comprises a data storage device including a number N of removable storage media for storing data, with N?2, and a number m of drives, with m?1, wherein each of the m drives is configured to drive one of the removable storage media mounted to the drive. The storage system includes a server being coupled to the data storage device and configured to serve requests from clients, and a controller which is configured to control the data storage device to adaptively unmount the removable storage media based on a monitoring information of the requests at the data storage device, states of the drives, and states of the removable storage media.

Abstract: Embodiments include methods for operating a first storage system having a first number of data storage drives for enabling access to a first set of removable media. Aspects include providing a second storage system having a number K of data storage drives for enabling access to a second set of removable media and providing a set of parameters describing operational characteristics of the second storage system. Aspects also include determining an analytical model using the set of parameters, the analytical model describing the variation of average waiting time as a function of system load over a predefined range covering multiple system load regime domains and determining values of the set of parameters using the analytical model and data of the second storage system. Aspects further include using the analytical model and the values of the set of parameters for reconfiguring the first storage system.

Abstract: Machines, systems and methods for optimizing data replication in a distributed storage network, the method comprising determining a need to create a replica for a data item in a remote failure zone in a data storage network; creating a temporary replica of the data item in a local failure zone defined in the data storage network, in response to determining that it is beneficial to create the temporary replica in the local failure zone based on a cost versus reliability improvement analysis; attempting to create the replica in the remote failure zone; and removing the temporary replica from the local failure zone, in response to successfully creating the replica in the remote failure zone.

Abstract: A method is provided for increasing data storage reliability in a heterogeneous storage system including multiple storage devices of two or more different types, the devices storing respective data subsets of a dataset.

Abstract: A storage system is proposed which comprises a data storage device including a number N of removable storage media for storing data, with N?2, and a number m of drives, with m?1, wherein each of the m drives is configured to drive one of the removable storage media mounted to the drive. The storage system includes a server being coupled to the data storage device and configured to serve requests from clients, and a controller which is configured to control the data storage device to adaptively unmount the removable storage media based on a monitoring information of the requests at the data storage device, states of the drives, and states of the removable storage media.

Abstract: Embodiments include methods, computer systems and computer program products for selecting a new redundancy scheme for data relocation in computer system having multiple data storage tiers and multiple redundancy schemes. Aspects include: receiving, at a processor of computer system, a request to relocate a data object to a destination data storage tier, retrieving a first and a second data reliability thresholds, redundancy scheme and data access pattern information of the data object, generating a set of available redundancy schemes for the data object with at least one copy on the destination data storage tier, calculating total cost for each of available redundancy schemes using performance cost, re-encoding cost, and storage cost for each of available redundancy schemes generated, selecting a redundancy scheme, and relocating data object to selected destination data storage tier by re-encoding the data object using the selected redundancy scheme.

Abstract: The present invention is notably directed to a computer-implemented method of accessing data by an application. The method comprises detecting an application that is accessing an initial file stored in a storage system; fetching an application model of the detected application, the application model comprising an association between access patterns of the detected application when accessing first files with first metadata information of the said first files; identifying one or more second files stored in the storage system, the identified one or more second files having second metadata information that are similar to the first metadata information; and prefetching the identified one or more second files.

Abstract: A storage system is proposed which comprises a data storage device including a number N of removable storage media for storing data, with N?2, and a number m of drives, with m?1, wherein each of the m drives is configured to drive one of the removable storage media mounted to the drive. The storage system includes a server being coupled to the data storage device and configured to serve requests from clients, and a controller which is configured to control the data storage device to adaptively unmount the removable storage media based on a monitoring information of the requests at the data storage device, states of the drives, and states of the removable storage media.

Abstract: A method for storing a data segment in a storage tier of a storage unit comprising at least two storage tiers includes receiving the data segment to be stored including metadata; receiving metadata of data segments stored in the storage unit; and determining the storage tier to store the received data segment to and a protection level dependent on the metadata received and dependent on the metadata of the received data segment.

Abstract: A method for storing a data segment in a storage tier of a storage unit comprising at least two storage tiers includes receiving the data segment to be stored including metadata; receiving metadata of data segments stored in the storage unit; and determining the storage tier to store the received data segment to and a protection level dependent on the metadata received and dependent on the metadata of the received data segment.

Abstract: A storage system and a method for storing a data segment, a storage capacity manager and a method for managing a capacity of a storage unit, and a storage tier relocation manager and a method for relocating a data segment. The storage system includes at least two storage tiers, an access pattern evaluator, a classification unit, a selector, and logic. The storage capacitor manager includes a monitoring unit and capacity managing unit. The storage tier relocation manager includes a target storage tier, the data segment relocated to the target storage tier, and a protection measure.

Abstract: A device and method for determining number of storage devices for each of plurality of storage tiers and assignment of data to be stored in the plurality of storage tiers. The device computes an optimized number of storage devices for each tier including a classifier, which receives units as input data to be stored in the system. Based on the characteristics of the storage devices, the device outputs a data-unit-to-storage tier assignment. An optimizer receives data-unit-to-storage tier assignment from the classifier and a cost budget for the system. Thereafter, an output for the number of storage devices for each storage tier is calculated. A method for determining number of storage devices for each of a plurality of storage tiers and assignment of data to be stored in the plurality of storage tiers are also provided.

Abstract: Machines, systems and methods for optimizing data replication in a distributed storage network, the method comprising determining a need to create a replica for a data item in a remote failure zone in a data storage network; creating a temporary replica of the data item in a local failure zone defined in the data storage network, in response to determining that it is beneficial to create the temporary replica in the local failure zone based on a cost versus reliability improvement analysis; attempting to create the replica in the remote failure zone; and removing the temporary replica from the local failure zone, in response to successfully creating the replica in the remote failure zone.

Abstract: A computing device writes data across storage devices in an erasure-coded system. The computing device computes data blocks and parity blocks from data and computes a portion of the data to be stored in the system. The computing is performed by one or more controllers included in a redundant array of an independent disks controller. The computing device provides the locations of the data blocks and the parity blocks in storage devices of an erasure-coded system. The location is determined using one or more placement nodes. The placement nodes are configured for managing placement schemes of data blocks and parity blocks on the storage devices.