A computer program product for migrating data in a computer storage system. Data is selected to migrate from a first storage to the second storage, wherein selected files are in a resident state. Metadata is obtaining and subsets of data are ordered based on the obtained metadata, the order of the subsets of data following an expectation of update value. The subsets of data are transferring to the second storage based on the order of the subsets of data based on a predetermined schedule. Data determined as inactive is overwritten on the sequential access medium by transferred data. End data to the sequential access medium is set after a last active data is written before the one or more sets of data are determined to be inactive. The one or more sets of data determined to be inactive are deleted from the second storage and a transfer is initiated.

A computer system for migrating data in a computer storage system. Data is selected to migrate from a first storage to the second storage, wherein selected files are in a resident state. Metadata is obtaining and subsets of data are ordered based on the obtained metadata, the order of the subsets of data following an expectation of update value. The subsets of data are transferring to the second storage based on the order of the subsets of data based on a predetermined schedule. Data determined as inactive is overwritten on the sequential access medium by transferred data. End data to the sequential access medium is set after a last active data is written before the one or more sets of data are determined to be inactive. The one or more sets of data determined to be inactive are deleted from the second storage and a transfer is initiated.

Retrieval of files containing audiovisual information from tape may be accelerated by reading from tape metadata in the files, storing the metadata in cache memory, and subsequently reading the file from tape, with reads of the metadata fulfilled from the cache. In some embodiments a memory map of objects in the file is created when the file is written to tape, and utilized to determine metadata locations in the file when reading the metadata to store in the cache.

In one embodiment, a system includes a disk cache and a controller configured to create a cache resident partition in the disk cache, the cache resident partition being configured to store data thereto that is not subject to HSM, manage the cache resident partition to have a size that is greater than a first minimum size and less than or equal to a total size of the disk cache, receive data to store to the disk cache, store the data to the cache resident partition at least initially, create tape-managed partitions in the disk cache, each of the tape-managed partitions being configured to store data that is subject to HSM, and manage the tape-managed partitions to have a size that is greater than a second minimum size and less than or equal to a total size of the disk cache less a size of all other partitions combined.

A system, method and computer program product for synchronizing data written to tape with improved data recovery. When writing data to tape, an index is kept in memory and updated to reflect change(s) to a file system mounted on tape. After a predetermined amount of data is written to a tape, a device may perform a sync operation, causing the index to be written into a data partition of the tape. If the sync operation is successful, the index in the index partition of the tape can be updated using a copy of the index in the data partition of the tape next time the tape is mounted. If the sync operation is not successful, the device may write the data to a different location on the same or another tape, update the index, and force another sync operation. This process can be repeated.

A tape recording device, method, and computer program product are provided for performing operations of position movement, reading, and writing on a tape medium, and receiving a series of commands from an upper-layer device. The tape recording device includes a buffer for temporarily storing data related to the reading and an append write, a tape for recording the data stored in the buffer, a reading and writing head for reading data from the tape into the buffer and writing the data onto the tape, control means for reading data from a designated position of the tape and storing the data in the buffer, and for writing the data stored in the buffer onto the tape from a written data end position in response to an append write command, and a non-volatile memory for storing data stored in the buffer in response to an append write command.

Example memory access popularity statistics methods and apparatus are described. One example method includes determining a first address based on an access request. The access request indicates an operation performed on a memory of a computer device by an application program run by at least one processor in the computer device. Statistics about access frequency of accessing a data block stored at the first address is collected. An access popularity of the data block is determined based on the access frequency.

In a general embodiment, a method includes storing hierarchically-organized global configuration information for each node and each tape library resource in a storage cluster to at least one memory accessible by each node of the storage cluster, the storage cluster comprising at least one tape library. The method further includes migrating and/or recalling, using the hierarchically-organized global configuration information, data to and/or from a tape cartridge pool within a tape library. The migration or recall is performed by an appropriate node of the storage cluster and in response to receiving a migration or recall request at an arbitrary node of the storage cluster.

Data is relocated, based on an intelligent data placement algorithm, from a first storage location to a second storage location in a disk storage system. A data placement record is generated including a virtual disk location associated with the data, the second storage location, and a first sequence value. The first sequence value indicates relative sequence when compared to other sequence values. The data placement record is written to a first record location on a first tape cartridge loaded in a tape drive. The data placement records are used with data records to restore data to disk storage from tape backup.

A method for dynamically changing a buffer threshold in a tape drive, according to another embodiment, includes monitoring a history of sizes of data transactions between sync commands, the data transactions being from a host to a tape drive, determining that a next sync command is expected to be received relatively sooner or relatively later based on the history of data size transactions, writing buffered data to a magnetic recording tape in response to determining that the next sync command will be received relatively sooner, and increasing a buffer threshold for delaying writing to the magnetic recording tape in response to determining that the next sync command will be received relatively later. A computer program product according to one embodiment includes a computer readable storage medium having program code embodied therewith, the program code readable/executable by a processor to perform the foregoing method.