Abstract: Assignment of files to a de-duplication domain. Address space of data files is divided into multiple containers. For each of the containers, a file metadata scan is performed to obtain file system metadata, which is aggregated and summarized in a content feature summary. A content feature summary prediction measurement is measured between containers from the generated content feature summary, and files from each container are assigned to a de-duplication domain based upon the content similarity predication measurement.

Abstract: Migrating a sub-volume in data storage with at least two de-duplication domains, each of the domains having at least one sub-volume. A first sub-volume is assigned to a de-duplication domain and a first content summary is computed for the first sub-volume. Similarly, a second sub-volume is assigned to a second de-duplication domains and a second content summary is computed for the second sub-volume. A first content affinity is calculated between the first sub-volume and a third sub-volume, and a second content affinity is calculated between the second sub-volume and the third sub-volume. A domain placement is selected for the third sub-volume based on comparison of the first content affinity and the second content affinity.

Abstract: Aspects of the invention are provided for decoding a selected span of data within a compressed code stream. A selection of data within the compressed code stream from an arbitrary position is presented for decompression. The arbitrary position is the starting point in the compressed code stream for decompression, and a phrase within the compressed code stream containing the starting point is identified. From the arbitrary starting point, a back pointer may provide direction to the literal. The literal is extracted as a decoding of the compressed data associated with the starting point.

Abstract: Aspects of the invention are provided for decoding a selected span of data within a compressed code stream. A selection of data within the compressed code stream from an arbitrary position is presented for decompression. The arbitrary position is the starting point in the compressed code stream for decompression, and a phrase within the compressed code stream containing the starting point is identified. From the arbitrary starting point, a back pointer may provide direction to the literal. The literal is extracted as a decoding of the compressed data associated with the starting point.

Abstract: Methods, systems, and computer program products are provided for deduplicating data mapping a plurality of file blocks of selected data to a plurality of logical blocks, deduplicating the plurality of logical blocks to thereby associate each logical block with a corresponding physical block of a plurality of physical blocks located on a physical memory device, two or more of the corresponding physical blocks being non-contiguous with each other, determining whether one or more of the corresponding physical blocks are one or more frequently accessed physical blocks being accessed at a frequency above a threshold frequency and being referred to by a common set of applications, and relocating data stored at the one or more frequently accessed physical blocks to different ones of the plurality of physical blocks, the different ones of the plurality of physical blocks being physically contiguous.

Abstract: Data deduplication for data storage tapes comprises determining the read throughput of a deduplicated set of individual files on a single data storage tape, and determining a placement of deduplicated file data on a single data storage tape to reduce an average number of per-file gaps on the tape. Deduplicated file data is placed on the single data storage tape based on said placement to increase an average read throughput for a deduplicated set of individual files.

Abstract: Embodiments of the present invention provide a system, method and computer program products for estimating data reduction in a file system. A method includes selecting a sample of all data from data files in the file system, wherein said sample represent a subset of all the data in the file system. The method further includes estimating a data reduction ratio by data deduplication for the file system based on said sample. The method further includes estimating a data reduction ratio by data compression for the file system based said sample. The method further includes generating a combined data reduction estimate for the file system based on said data compression estimate and said data deduplication estimate.

Abstract: Detecting data duplication comprises maintaining a fingerprint directory including one or more entries, each entry including a data fingerprint and a data location for a data chunk. Each entry is associated with a seen-count attribute which is an indication of how often the fingerprint has been seen in arriving data chunks. Higher-frequency entries in the directory are retained, while also taking into account recency of data accesses. A data duplication detector detects that the data fingerprint for a new chunk is the same as the data fingerprint contained in an entry in the fingerprint directory.

Abstract: Data reduction in a storage system comprises determining attributes of data for storage in the storage system and determining expected data reduction effectiveness for the data based on said attributes. Said effectiveness indicates the benefit that data reduction is expected to provide for the data based on said attributes. The data reduction further comprises applying data reduction to the data based on the expected data reduction effectiveness and performance impact, to improve resource usage efficiency.

Abstract: Embodiments of the present invention provide a system, method and computer program products for estimating data reduction in a file system. A method includes selecting a sample of all data from data files in the file system, wherein said sample represent a subset of all the data in the file system. The method further includes estimating a data reduction ratio by data deduplication for the file system based on said sample. The method further includes estimating a data reduction ratio by data compression for the file system based said sample. The method further includes generating a combined data reduction estimate for the file system based on said data compression estimate and said data deduplication estimate.

Abstract: Embodiments of the present invention provide an approach for migrating virtual machines across network (e.g., WAN) separated data centers (e.g., storage clouds). Specifically, under embodiments of the present invention, a first storage system associated with a first data center is synchronized with a second storage system associated with a second data center via a storage system link. Then, a minimal state of a virtual machine is migrated from a first computer in the first data center to a second computer in the second data center via a WAN link. Using the minimal state, the virtual machine is stored in the second computer. Thereafter, the storage system link is terminated. In addition, as updated pages are received in memory of the first computer, they are migrated to the second computer via the WAN link. Once this migration is complete, the WAN link can be terminated.