Abstract: An apparatus according to one embodiment includes a controller configured to control writing operations to a magnetic recording tape, and logic integrated with and/or executable by the controller for causing the controller to receive a plurality of records, store datasets associated with the plurality of records in a buffer memory, and write the datasets stored in the buffer memory to the magnetic recording tape in response to a predetermined number of datasets being stored in the buffer memory. For each of the datasets being written, an end longitudinal position indicative of a physical position where the dataset is physically written to the magnetic recording tape is determined. Moreover, for each determined end longitudinal position, the end longitudinal position and an identifier of the associated dataset are stored to a table of a dataset that is to be subsequently written to the magnetic recording tape.

Abstract: A computer-implemented method, a computer program product, and a computer system for optimizing timing for migrating data. The computer system sets a migration required flag for each of first tapes, in response to determining an estimated time period required for data migration from the first tapes to second tapes being smaller than an expiration time period of the first tapes. The computer system sets the migration required flag for a respective one of the first tapes, in response to determining the estimated time period being not smaller than the expiration time period and a predetermined time period has passed for the respective one of the first tapes. Data on tapes that migration required flags are set is to be migrated to the second tapes.

Abstract: A computer-implemented method for writing data to a tape medium, includes: writing a file of a first content to the tape medium; writing at least a part of the file of a second content to the tape medium, the second content being obtained by updating the first content; and writing an index including first metadata and second metadata to the tape medium, the first metadata being metadata of the file of the first content, the second metadata being metadata of the file of the second content.

Abstract: A computer-implemented method for faster unmount of tape drives includes generating a batch file to be migrated from a primary storage to a tape media acting as a secondary storage. The size of the batch file is determined based on an amount of available storage space on the tape media between a position in a longitudinal direction of storage (LPOS) and longitudinal position three (LP3) on the tape media. The computer-implemented method further includes migrating the batch file from the primary storage to the tape media mounted on a tape drive. Upon completion of migrating the batch file, the LPOS is within a predetermined threshold distance of LP3 on the tape media.

Abstract: Aspects of the present disclosure relate to managing index writes within a tape. A determination can be made that a change was made to at least one file stored within a tape medium while the tape medium was mounted within a tape drive. In response to the determination, an index can be written to a data partition of the tape medium. A determination can be made whether the change included any changes to a file at least equal to a threshold hierarchy level. In response to determining that the change did not include any changes to a file at least equal to the threshold hierarchy level, a first instruction can be issued to the tape drive to reposition the tape medium to the end of the tape. A second instruction can be issued to the tape drive to perform an unthread operation at low tension to rewind the tape medium.

Abstract: Method, computer program product, and system embodiments of the present disclosure may include a computing device which may set a predetermined flag on data to be copied from a primary storage tier and a secondary storage tier. The computing device may identify a first portion of the flagged data as being in a pre-migrated state stored on the primary storage tier and migrate the flagged pre-migrated data from the primary storage tier to a target medium. The computing device may identify a second portion of the flagged data as being in a migrated state stored on the secondary storage tier. The computing device may recall the flagged migrated data from the secondary storage tier to the primary storage tier and migrate the recalled migrated data from the primary storage tier to the target medium.

Abstract: A computer-implemented method, a computer program product, and a computer system for reordering a sequence of files based on compression rates in data transfer. A host determines predicted compression rates of first files that are to be saved onto a first tape, based on a relationship between compression rates and file attributes of second files that have been saved on a second tape. The host reorders a sequence of the first files stored in host cache storage and generates a new sequence of transferring the first files from the host cache storage to the tape drive hosting the first tape, based on the predicted compression rates of the first files. The host transfers the first files to the tape drive hosting the first tape and writes the first files to the first tape, according to the new sequence.

Abstract: An apparatus according to one embodiment includes a controller configured to control writing operations to a magnetic recording tape. The apparatus further includes logic integrated with and/or executable by the controller for causing the controller to write user data to the magnetic recording tape in a user data area of the magnetic recording tape. Furthermore, the logic is integrated with and/or executable by the controller for causing the controller to create a housekeeping data set (HKDS) that includes location information for the user data written in the user data area, and write several copies of the HKDS in a non-user data area of the magnetic recording tape.

Abstract: A computer-implemented method for incrementing a tape write pass (WP) value includes identifying an action that requires incrementing a tape WP value on a magnetic tape storage device. The computer-implemented method further includes, in response to identifying the action that requires incrementing the tape WP value on the magnetic tape storage device: assigning a new tape WP value to a dataset based, at least in part, on a partition number corresponding to the data partition in which the dataset is written to.

Abstract: Aspects of the present disclosure relate to synchronizing data writes. An update to a file stored on a virtual tape image is received. A position and length of the file is recorded as an invalid data area. The virtual tape image is then synchronized with a tape. The invalid data area is then released from the virtual tape image.

Abstract: Provided is a method, computer program product, and system for enumerating files on a tape medium and a cache storage device. The method includes receiving a command to enumerate a directory stored on a tape medium. The directory includes a plurality of files. The method further includes determining that the directory has been at least partially cached to a cache storage device. The method further includes determining, for each file of the directory that is stored in the cache storage device, whether the file has been enumerated. In response to determining that the file has not been enumerated, the method includes returning information of the file as a response to the command. The method further includes mounting the tape medium in parallel to retrieving data from the cache storage device.

Abstract: Provided is a method for writing and deleting files on a tape medium and a cache storage device. The method includes receiving a command to write one or more files of a directory to a tape medium. The method further includes identifying a cache limit associated with the tape medium. The method further comprises determining whether the amount of data of the directory that is already on the cache storage device exceeds the cache limit. In response to the amount of data not exceeding the cache limit, the method includes writing data of the one or more files to the cache storage device and the tape medium in parallel.

Abstract: A read error occurs when performing a read with a first read head. It is determined whether a second read head capable of use in a read-while-write operation runs within or outside of a first track. The second read head width defines a verified area on a track. If the second read head runs entirely within the first track, the first read head is positioned within the verified area. If the second read head runs partly outside of the first track, and a portion of the verified area within the first track is wider than the width of the first read head, the first read head is positioned within the portion of the verified area that is within the first track. If the portion is not wider, the first read head is positioned so that a side of the first read head is at a border the first track.

Abstract: An apparatus according to one embodiment includes a controller configured to control writing operations to a magnetic recording tape. The apparatus further includes logic integrated with and/or executable by the controller for causing the controller to write user data to the magnetic recording tape in a user data area of the magnetic recording tape. Furthermore, the logic is integrated with and/or executable by the controller for causing the controller to create a housekeeping data set (HKDS) that includes location information for the user data written in the user data area, and write several copies of the HKDS in a non-user data area of the magnetic recording tape.

Abstract: A computer-implemented method for managing a first storage library and a second storage library, according to one embodiment, includes associating a first physical tape and a second physical tape with a logical tape. The associating includes writing a first identifier to an index of the logical tape. The first identifier represents the first physical tape and the first storage library. The associating further includes writing a second identifier to the index of the logical tape. The second identifier represents the second physical tape and the second storage library. The computer-implemented method further includes storing the index of the logical tape in memory, and displaying the logical tape by reading the index from memory as a file system.

Abstract: A method for restoring a target file system in a storage system by a computer system, the computer system being connected to a network, the storage system including a tier of sequential access media, the method includes receiving a backup image including metadata of a file of the target file system, from a remote computer system via the network, the metadata indicating a sequential access medium, and restoring the metadata of the target file system using the backup image, the target file system being restored on the computer system by sharing a resource with a native file system operating on the computer system.

Abstract: Aspects of the present disclosure relate to synchronizing data writes. An update to a file stored on a virtual tape image is received. A position and length of the file is recorded as an invalid data area. The virtual tape image is then synchronized with a tape. The invalid data area is then released from the virtual tape image.

Abstract: A method for avoiding inode number conflict during metadata restoration at a restoration location is provided. The method includes receiving metadata for a first file including an inode containing an initial internal inode number and a directory entry containing an external inode number, determining an allocation status of the initial internal inode number at the restoration location, identifying an available internal inode number to be allocated to the first file, updating the initial internal inode number in the inode for the first file with the available internal inode number, registering the available internal inode number and the external inode number in an inode mapping table indicating correspondence between the available internal inode number and the external inode number, and restoring the inode based on the available internal inode number.

Abstract: Provided is a method, computer program product, and system for handling seek commands for a tape drive. The method includes receiving a seek command for moving tape in the tape drive to a target position. The method further includes determining whether to move the tape according to a first procedure or a second procedure. The first procedure includes directly moving the tape from the current position to the target position with the tape at the first tension. The second procedure includes moving the tape from the current position to the HWM with the tape at the first tension and moving the tape from the HWM to the target position with the tape at the second tension. The method further includes moving the tape according to the determined first or second procedure.

Abstract: A backup method is provided for a file system for managing hierarchical storage including one or more storage media on a computer system including one or more computers. Each of the one or more storage media includes a data part which is separated from an index and on which updated information is appended and kept. Each of a plurality of pieces of data within the file system is managed to be migrated to at least any of the one or more storage media. The backup method includes backing up metadata of the plurality of pieces of data migrated within the file system; and backing up the index of each of the one or more storage media to which the plurality of pieces of data have been migrated, substantially at the same time point as the metadata.