Abstract: According to one embodiment, a storage apparatus includes a first storage unit, a second storage unit and a control module. The control module stores the address of a block data item and a block identifier unique to the block data item, included in a write request, in the second storage unit such that the address and the block identifier are associated with each other when a request to specify the writing of data including the block data item into the storage apparatus has been generated at a host apparatus and when the host apparatus has transmitted the write request because the data item has coincided with any one of the block data items stored in the cache of the host apparatus.

Abstract: According to one embodiment, a storage apparatus includes a first storage unit, a second storage unit and a control module. The control module stores the address of a block data item and a block identifier unique to the block data item, included in a write request, in the second storage unit such that the address and the block identifier are associated with each other when a request to specify the writing of data including the block data item into the storage apparatus has been generated at a host apparatus and when the host apparatus has transmitted the write request because the data item has coincided with any one of the block data items stored in the cache of the host apparatus.

Abstract: An identifier generation unit generates first identifiers corresponding to a plurality of first fragmentary data, into which first data that is stored in a database is divided. A database stores the first data and the first identifiers. The identifier generation unit generates, when the first data is updated to second data, second identifiers corresponding to a plurality of second fragmentary data into which the second data is divided. A deployment control unit determines whether the first identifiers are identical to the second identifiers which correspond to the first identifiers. The deployment control unit writes in the database the second fragmentary data corresponding to the second identifiers and the second identifiers when it is determined that the first identifiers are not identical to the second identifiers which correspond to the first identifiers.

Abstract: An overlay network system comprises an overlay network composed of a plurality of nodes and a plurality of sub-overlay networks each of which is composed of a subset of the plurality of nodes and which are hierarchized. The overlay network is managed as a 0th-level sub-overlay network at the highest hierarchical level. Each of the plurality of sub-overlay networks is allocated a sub-overlay network ID whose number of bits corresponds to the hierarchical level of the network. The high-order one or more bits in the sub-overlay network ID also indicate the sub-overlay network ID of a sub-overlay network at the high hierarchical level corresponding to the number of the one or more bits.

Abstract: Nodes include controllers, management servers, and storages. Each of the controllers includes a first mapping table indicating management servers corresponding to logical extents that compose a logical volume that is provided for a host. The management servers include second mapping tables indicating which nodes include storages that store logical extents corresponding to the management servers. The storages include third mapping tables indicating which physical extents of physical volumes included in the storages store the logical extents.

Abstract: A method for management of access history according to the embodiment includes: storing a write command including write time and a write address of write access and a write payload in a storage unit of write access history when the write access occurs; storing a read command including read time and read address of read access in a storage unit of read access history when the read access to the target storage unit occurs; and extracting the read command related to request time included in a read access acquisition request from the storage unit of read access history when the read access acquisition request occurs, extracting the write payload associated with the write time soonest before the request time and the read address included in the extracted read command from an appending section of write access history, and outputting read access information generated from the extracted read command and the extracted write payload.

Abstract: An overlay network system comprises an overlay network composed of a plurality of nodes and a plurality of sub-overlay networks each of which is composed of a subset of the plurality of nodes and which are hierarchized. The overlay network is managed as a 0th-level sub-overlay network at the highest hierarchical level. Each of the plurality of sub-overlay networks is allocated a sub-overlay network ID whose number of bits corresponds to the hierarchical level of the network. The high-order one or more bits in the sub-overlay network ID also indicate the sub-overlay network ID of a sub-overlay network at the high hierarchical level corresponding to the number of the one or more bits.

Abstract: A relay unit inputs data and an index. A cache management unit determines whether or not a space area to cache data exists. In the case where there is a space area, the cache management unit caches data. An identifier generating unit generates an identifier corresponding to contents of the cached data. The identifier is registered in a cache data table in association with the data. The identifier is registered in a cache index table in association with the index. In the case where there is no space area, the cache management unit secures a space area. The cache management unit unregisters an identifier associated with the data which was cached in the secured area.

Abstract: An identifier generation unit generates first identifiers corresponding to a plurality of first fragmentary data, into which first data that is stored in a database is divided. A database stores the first data and the first identifiers. The identifier generation unit generates, when the first data is updated to second data, second identifiers corresponding to a plurality of second fragmentary data into which the second data is divided. A deployment control unit determines whether the first identifiers are identical to the second identifiers which correspond to the first identifiers. The deployment control unit writes in the database the second fragmentary data corresponding to the second identifiers and the second identifiers when it is determined that the first identifiers are not identical to the second identifiers which correspond to the first identifiers.

Abstract: Nodes include controllers, management servers, and storages. Each of the controllers includes a first mapping table indicating management servers corresponding to logical extents that compose a logical volume that is provided for a host. The management servers include second mapping tables indicating which nodes include storages that store logical extents corresponding to the management servers. The storages include third mapping tables indicating which physical extents of physical volumes included in the storages store the logical extents.

Abstract: A method for management of access history according to the embodiment includes: storing a write command including write time and a write address of write access and a write payload in a storage unit of write access history when the write access occurs; storing a read command including read time and read address of read access in a storage unit of read access history when the read access to the target storage unit occurs; and extracting the read command related to request time included in a read access acquisition request from the storage unit of read access history when the read access acquisition request occurs, extracting the write payload associated with the write time soonest before the request time and the read address included in the extracted read command from an appending section of write access history, and outputting read access information generated from the extracted read command and the extracted write payload.