Abstract: There is provided a storage subsystem having a virtual volume and a page volume which has a page physical area allocated to the virtual volume. The storage subsystem divides an address space of the virtual volume into a plurality of pages, classifies each of the pages into one of a plurality of states including at least a first state and a second state, and further divide a page which is classified into the second state into a plurality of segments to managed the page classified into the second state. The first state is a state in which a page physical area is allocated to the page from the page volume, and the write data is stored in the page physical area. The second state is a state in which the predetermined pattern data and the segment are managed, in the memory, by correlating with each other.

Abstract: A distributed storage system has MDSs (metadata servers). Directories of file system namespace are distributed to the MDSs based on hash value of inode number of each directory. Each directory is managed by a master MDS. When a directory grows with a file creation rate greater than a preset split threshold, the master MDS constructs a consistent hashing overlay with one or more slave MDSs and splits directory entries of the directory to the consistent hashing overlay based on hash values of file names under the directory. The number of MDSs in the consistent hashing overlay is calculated based on the file creation rate. When the directory continues growing with a file creation rate that is greater than the preset split threshold, the master MDS adds a slave MDS into the consistent hashing overlay and splits directory entries to the consistent hashing overlay based on hash values of file names.

Abstract: A storage controller comprises a cache storage used as a cache of an external storage and a control processor coupled to the cache storage. The control processor comprises an internal access function and an external access function. The internal access function transmits a read command to the cache storage. The cache storage determines whether the read target data complying with the read command is stored in a physical storage device or not. If the result of the determination is negative, the external access function is executed while, if the result of the determination is positive, the external access function is not executed because the cache storage transmits the read target data to the internal access function without issuing a request to the external access function.

Abstract: To enhance capacity expansion property of a storage system for providing thin provisioning logical volumes, a computer system includes a first storage system and a second storage system for providing a second volume to the first storage system. The first storage system is configured to define at least one first volume, define a first storage pool including the defined first volume and the provided second volume, and provide to the host computer a first thin provisioning volume that is recognized as a volume having a capacity equal to or larger than that of storage areas assigned from the first storage pool. The first thin provisioning volume is thus assigned with both storage areas of the first volume and storage areas of the second volume, which are included in the first storage pool.

Abstract: In a system of local DHT overlays, each has KVS nodes, including one super node. The super nodes organize a global DHT overlay. Each super node maintains Bloom filters of keys in its local DHT overlay for all key ranges. To obtain data corresponding to a key from other local DHT overlays, a super node sends a request to a node which is responsible for the key range hashed from the specified key. The responsible node determines local DHT overlays which may have data corresponding to the key according to Bloom filters registered in the super nodes of the local DHT overlays, updated and converted from counting filters. Requests are sent to the super nodes of the local DHT overlays identified by the responsible node. Thus, requests are not needlessly sent to super nodes of local DHT overlays which do not have data corresponding to the key, thereby reducing traffic.

Abstract: A pool is formed based on a plurality of storage devices. This pool is constituted by a plurality of real pages. Real pages of different lengths are included in this plurality of real pages. Among a plurality of virtual pages which make up a virtual volume, a controller compresses a write data element for a write destination virtual page, selects a real page of a real page length based on the data length of a data unit including the compressed write data element, and allocates the selected real page to the write destination virtual page.

Abstract: There is provided a storage subsystem having a virtual volume and a page volume which has a page physical area allocated to the virtual volume. The storage subsystem divides an address space of the virtual volume into a plurality of pages, classifies each of the pages into one of a plurality of states including at least a first state and a second state, and further divide a page which is classified into the second state into a plurality of segments to managed the page classified into the second state. The first state is a state in which a page physical area is allocated to the page from the page volume, and the write data is stored in the page physical area. The second state is a state in which the predetermined pattern data and the segment are managed, in the memory, by correlating with each other.

Abstract: A plurality of CPU cores each have control rights for logical storage areas of one or more types among logical storage areas of a plurality of types. As a source for an area to be assigned to the logical storage areas, a physical storage area which is common to the logical storage areas of the plurality of types is managed. In the case of a data access to a logical storage area corresponding to the control rights of the CPU core, the respective CPU core assigns an area required to store the data from the common physical storage area.

Abstract: A pool is formed based on a plurality of storage devices. This pool is constituted by a plurality of real pages. Real pages of different lengths are included in this plurality of real pages. Among a plurality of virtual pages which make up a virtual volume, a controller compresses a write data element for a write destination virtual page, selects a real page of a real page length based on the data length of a data unit including the compressed write data element, and allocates the selected real page to the write destination virtual page.

Abstract: In the process of controlling a plurality of storage devices 190 in any one of a normal mode and a plurality of power-saving modes (such as standby and LRPM), a controller 110 selects the storage devices whose mode should be shifted from the normal mode to any of the power-saving modes; and before shifting to control of the selected storage devices in any of the power-saving modes, the controller calculates time and electric power required to make the selected storage devices return from each power-saving mode to the normal mode; and based on each calculated value, the controller sets a combination of power-saving modes and the number of storage devices that satisfy the return conditions defined by the host timeout period and the supplied power; and then, the controller controls the selected number of storage devices in the set combination of power-saving modes.

Abstract: There is provided a storage subsystem having a virtual volume and a page volume which has a page physical area allocated to the virtual volume. The storage subsystem divides an address space of the virtual volume into a plurality of pages, classifies each of the pages into one of a plurality of states including at least a first state and a second state, and further divide a page which is classified into the second state into a plurality of segments to managed the page classified into the second state. The first state is a state in which a page physical area is allocated to the page from the page volume, and the write data is stored in the page physical area. The second state is a state in which the predetermined pattern data and the segment are managed, in the memory, by correlating with each other.

Abstract: A distributed storage system employs a Key-Value Store to dynamically change a table layout scheme based on user access patterns. The system can be used as a basic architecture to construct a distributed Key-Value Store to support both row-oriented and column-oriented table layout schemes, by using DHT (Distributed Hash Table) technology for high scalability.

Abstract: To enhance capacity expansion property of a storage system for providing thin provisioning logical volumes, a computer system includes a first storage system and a second storage system for providing a second volume to the first storage system. The first storage system is configured to define at least one first volume, define a first storage pool including the defined first volume and the provided second volume, and provide to the host computer a first thin provisioning volume that is recognized as a volume having a capacity equal to or larger than that of storage areas assigned from the first storage pool. The first thin provisioning volume is thus assigned with both storage areas of the first volume and storage areas of the second volume, which are included in the first storage pool.

Abstract: A pool is formed based on a plurality of storage devices. This pool is constituted by a plurality of real pages. Real pages of different lengths are included in this plurality of real pages. Among a plurality of virtual pages which make up a virtual volume, a controller compresses a write data element for a write destination virtual page, selects a real page of a real page length based on the data length of a data unit including the compressed write data element, and allocates the selected real page to the write destination virtual page.

Abstract: A controller for controlling a logical resource of a storage system comprises a virtual resource preparation section for preparing a virtual resource which is a virtual logical resource, and a real resource assignment section that assigns a real resource which is a logical resource of a real entity to the prepared virtual resource. One or more backup resources which are virtual resources that have not yet been used by a higher-level section that is on a higher level than the controller are prepared by the virtual resource preparation section for one or more of the higher-level section.

Abstract: To enhance capacity expansion property of a storage system for providing a thin provisioning volume, this invention provides a computer system including: a first storage system; and a second storage system for providing a second volume to the first storage system. The first storage system is configured to: define at least one first volumes; define a first storage pool including the defined first volume and the provided second volume; provide to the host computer a first thin provisioning volume that is recognized as a volume having a capacity equal to or larger than that of storage areas assigned from the first storage pool. The first thin provisioning volume is thus assigned with both storage areas of the first volume and storage areas of the second volume, which are included in the first storage pool.

Abstract: The storage device of the present invention has: a first recording unit that records a time zone history of access to each storage area assigned to a virtual volume; a second recording unit that executes a predetermined calculation based on the time zone history of access to a plurality of storage areas belonging to a plurality of pool areas and records the calculation result for each of the plurality of pool areas; a comparison unit that acquires, from the first recording unit, the time zone history of access to an optional storage area among the plurality of storage areas and compares the acquired access time zone history with the calculation result recorded in the second recording unit; and a migration unit that selects, from among the plurality of pool areas, a pool area for which the calculation result is similar to the acquired access time zone history on the basis of the result of the comparison by the comparison unit, and migrates the data stored in the optional storage area to a storage area in the s

Abstract: A pool is formed based on a plurality of storage devices. This pool is constituted by a plurality of real pages. Real pages of different lengths are included in this plurality of real pages. Among a plurality of virtual pages which make up a virtual volume, a controller compresses a write data element for a write destination virtual page, selects a real page of a real page length based on the data length of a data unit including the compressed write data element, and allocates the selected real page to the write destination virtual page.

Abstract: The invention is directed to a load sharing method in a computer system including a first storage subsystem, a host computer, and a management computer. In the computer system, the first storage subsystem creates a plurality of first logical units from a storage area of a disk drive group, and the host computer creates a logical storage area configured by a plurality of virtual logical units respectively corresponding to the first logical units. A communications path is set between the host computer and each of the first logical units configuring the logical storage area. The load sharing method includes the steps of: monitoring, by the first storage subsystem, a load of its own; and changing, by the first storage subsystem, the communications paths between the host computer and the first logical units based on the monitoring result of the load.

Abstract: A storage controller comprises a cache storage used as a cache of an external storage and a control processor coupled to the cache storage. The control processor comprises an internal access function and an external access function. The internal access function transmits a read command to the cache storage. The cache storage determines whether the read target data complying with the read command is stored in a physical storage device or not. If the result of the determination is negative, the external access function is executed while, if the result of the determination is positive, the external access function is not executed because the cache storage transmits the read target data to the internal access function without issuing a request to the external access function.