Described in detail herein are systems and methods for managing single instancing data. Using a single instance database and other constructs (e.g. sparse files), data density on archival media (e.g. magnetic tape) is improved, and the number of files per storage operation is reduced. According to one aspect of a method for managing single instancing data, for each storage operation, a chunk folder is created on a storage device that stores single instancing data. The chunk folder contains three files: 1) a file that contains data objects that have been single instanced; 2) a file that contains data objects that have not been eligible for single instancing; and 3) a metadata file used to track the location of data objects within the other files. A second storage operation subsequent to a first storage operation contains references to data objects in the chunk folder created by the first storage operation instead of the data objects themselves.

Multiple data paths may be available to a data management system for transferring data between a primary storage device and a secondary storage device. The data management system may be able to gain operational advantages by performing load balancing across the multiple data paths. The system may use application layer characteristics of the data for transferring from a primary storage to a backup storage during data backup operation, and correspondingly from a secondary or backup storage system to a primary storage system during restoration.

An information processing apparatus, backup method, and program product that enable efficient differential backup. In one embodiment, an information processing apparatus for files stored in a storage device includes: a metadata management unit for managing metadata of files stored in the storage device; a map generation unit for generating a map which indicates whether metadata associated with an identification value uniquely identifying a file in the storage device is present or absent; and a backup management unit for scanning the metadata to detect files that have been created, modified, or deleted since the last backup, and storing at least a data block and the metadata for a detected file in a backup storage device as backup information in association with the identification value.

A memory device system includes: a first memory that has m lines of addresses and in which different pieces of data are respectively stored at the m lines of addresses, and a parity bit; a second memory that has m lines of addresses and in which same pieces of data as the pieces of data stored in the first memory are stored in an initial state; a first register that is connected with the first memory; a second register that is connected with the second memory; a comparator; a transfer register that stores the piece of data of the first memory; an error data register that stores the piece of data of the second register; an error address register that stores an address of the second memory; a parity calculation portion that calculates parity of all pieces of data; and a controller that performs a predetermined control.

Described are methods, systems and computer readable media for performance logging of complex query operations.

Some examples described herein relate to data restoration. In an example, checkpoints may be defined for converting backup data stored in each of Logical Unit Numbers (LUNs) of a storage system into respective virtual data disk files. Backup data stored in each of the LUNs of the storage system may be converted into respective virtual data disk files at the defined checkpoints. The virtual data disk files with user configuration information of the storage system may be packaged into a Virtual Storage Appliance (VSA), which may include a base operating system (OS) image of the VSA. The VSA may be transferred to an external entity.

Methods and systems for managing manifests for replication are provided. A system includes a number of origination nodes forming a source array. A remote copy ticket dispenser provides a replication ticket for a transaction to be grouped with other transactions and to be replicated to a destination array. A transaction communicator sends transactions to the destination array.

One example method includes gathering respective performance data concerning each asset in a group of assets, clustering the performance data so as to define a first cluster and a second cluster, and data assets in the first cluster are assigned a HIGH RISK label and data assets in the second cluster are assigned a LOW RISK label, assigning a respective risk score to each of the assets, and the risk score includes a quantified risk level for the asset to which the risk score has been assigned, ranking the assets with the HIGH RISK label according to their respective risk scores, and backing up a ranked asset based on an IO volume associated with that ranked asset.

Multiple data paths may be available to a data management system for transferring data between a primary storage device and a secondary storage device. The data management system may be able to gain operational advantages by performing load balancing across the multiple data paths. The system may use application layer characteristics of the data for transferring from a primary storage to a backup storage during data backup operation, and correspondingly from a secondary or backup storage system to a primary storage system during restoration.

One example method includes optimizing client-side deduplication. When backing up a client, an overwrite ratio is determined based on a size of actual changes made to a volume and a size indicated by changes in a change log. Client-side deduplication is enabled or disabled based on a value of the overwrite ratio.