Abstract: When computers and virtual machines operating in the computers both attempt to allocate a cache regarding the data in a secondary storage device to respective primary storage devices, identical data is prevented from being stored independently in multiple computers or virtual machines. An integrated cache management function in the computer arbitrates which computer or virtual machine should cache the data of the secondary storage device, and when the computer or the virtual machine executes input/output of data of the secondary storage device, the computer inquires the integrated cache management function, based on which the integrated cache management function retains the cache only in a single computer, and instructs the other computers to delete the cache. Thus, it is possible to prevent identical data from being cached in a duplicated manner in multiple locations of the primary storage device, and enables efficient capacity usage of the primary storage device.

Abstract: An example of storage system obtains a reference request of a reference request data block that is included in the content and is stored in the medium area. The storage system determines a number of gaps among addresses, in the medium area, of a plurality of data blocks continuous in the content including the reference request data block. The storage system determines, based on the number of gaps, whether or not defrag based on the plurality of data blocks is valid. The storage system writes, when the defrag is determined to be valid, the plurality of data blocks read from the medium area to the memory area, into continuous address areas of the medium area.

Abstract: A method switches file server from old file server to new file server which are coupled via a backend network and provides data synchronization. The old file server and new file server are coupled with one or more host computers via a frontend network to direct input/output (I/O) requests from the one or more host computers. The method comprises creating stub files in the new file server, the stub files including stub information indicating location of data in the old file server; switching I/O requests directed to old file server to I/O requests directed to the new file server; checking whether the new file server has any stub files; and, if the new file server has one or more stub files, recalling data corresponding to the one or more stub files from the old file server according to the stub information to replace the one or more stub files.

Abstract: When computers and virtual machines operating in the computers both attempt to allocate a cache regarding the data in a secondary storage device to respective primary storage devices, identical data is prevented from being stored independently in multiple computers or virtual machines. An integrated cache management function in the computer arbitrates which computer or virtual machine should cache the data of the secondary storage device, and when the computer or the virtual machine executes input/output of data of the secondary storage device, the computer inquires the integrated cache management function, based on which the integrated cache management function retains the cache only in a single computer, and instructs the other computers to delete the cache. Thus, it is possible to prevent identical data from being cached in a duplicated manner in multiple locations of the primary storage device, and enables efficient capacity usage of the primary storage device.

Abstract: In the present invention, when configuration data art a LFS (Log-Structured File system) is stored on a virtual volume constructed from a plurality of Storage mediums, a temporal change of the file size on the file system is roughly estimated. Then, in accordance with the change, a capacity that is needed on the virtual volume is provided, a cursor at the end of a log is set, and a write cursor for writing data is set so as to avoid the position behind the cursor at the end of the log. Accordingly, it is possible to, when the LFS occupies only a small area on the virtual volume, avoid early execution of the allocation of an available capacity, and thus avoid a circumstance in which a large number of storage mediums are needed at an early stage of the operation of the virtual volume (see FIG. 1).

Abstract: In the present invention, when configuration data on a LFS (Log-Structured File system) is stored on a virtual volume constructed from a plurality of storage mediums, a temporal change of the file size on the file system is roughly estimated. Then, in accordance with the change, a capacity that is needed on the virtual volume is provided, a cursor at the end of a log is set, and a write cursor for writing data is set so as to avoid the position behind the cursor at the end of the log. Accordingly, it is possible to, when the LFS occupies only a small area on the virtual volume, avoid early execution of the allocation of an available capacity, and thus avoid a circumstance in which a large number of storage mediums are needed at art early stage of the operation of the virtual volume (see FIG. 1).

Abstract: When processing data via multiple computers, the number of computers can be increased or decreased without actually moving the data assigned to the respective computers, and the data can be arranged and processed so as to enhance the performance of the system in response to the increase of the number of computers. A plurality of computers for performing data processing stores target data to be processed in a shared storage system, and when data processing is to performed, the shared storage divides the storage area storing data corresponding to the number of computers, and creates virtual data storage areas referring to a portion of the storage area for each computer, so as to enable each computer to refer to independent virtual data storage areas and to complete data processing.

Abstract: A file storage performs control to create a virtual parent file having an identifier capable of uniquely identifying a parent file among storage systems and volumes, and to acquire block layout information of the parent file using said identifier. The file storage creates a virtual parent file in the volume in which the clone file is created, and sets the file as a virtual parent file of the clone file so as to enable creation of a clone file of a parent file that exists in a different volume or a different storage system. Moreover, by combining creating the virtual parent file and switching the identifier of the parent file which is pointed by the virtual parent file, migration of clone files and parent files astride storage systems and volumes is enabled.

Abstract: An aspect of this invention is a computer system, including: a storage apparatus for allocating real storage areas of a plurality of tiers of a tiered real storage area pool to a volume, and migrating and relocating data within the volume between the plurality of tiers; and a host apparatus that accesses the volume provided by the storage apparatus. The host apparatus is configured to refer to tier information including information on a corresponding one of the plurality of tiers to which an access destination address within the volume belongs to identify the corresponding one of the plurality of tiers to which the access destination address belongs and refer to settings predetermined for the plurality of tiers to perform I/O control for the access destination address based on settings of the identified corresponding one of the plurality of tiers.

Abstract: A method switches file server from old file server to new file server which are coupled via a backend network and provides data synchronization. The old file server and new file server are coupled with one or more host computers via a frontend network to direct input/output (I/O) requests from the one or more host computers. The method comprises creating stub files in the new file server, the stub files including stub information indicating location of data in the old file server; switching I/O requests directed to old file server to I/O requests directed to the new file server; checking whether the new file server has any stub files; and, if the new file server has one or more stub files, recalling data corresponding to the one or more stub files from the old file server according to the stub information to replace the one or more stub files.

Abstract: A method switches file server from old file server to new file server which are coupled via a backend network and provides data synchronization. The old file server and new file server are coupled with one or more host computers via a frontend network to direct input/output (I/O) requests from the one or more host computers. The method comprises creating stub files in the new file server, the stub files including stub information indicating location of data in the old file server; switching I/O requests directed to old file server to I/O requests directed to the new file server; checking whether the new file server has any stub files; and, if the new file server has one or more stub files, recalling data corresponding to the one or more stub files from the old file server according to the stub information to replace the one or more stub files.

Abstract: In an information system which includes a local site including a cache file server coupled with a host computer, and a remote site including a remote file server coupled with a surrogate processing computer, a method determines whether each of one or more files of data for a data processing request is cached or not. If yes, the method executes data processing for each cached file to produce results in local site. If no, the method includes creating a file list of files to be processed in remote site; sending the file list and processing program to the surrogate computer; if the processing is sufficiently effective to be done by the surrogate computer, receiving results of the processing executed in remote site, and, if not, then receiving an unprocessed file list from remote site and executing data processing in local site and receiving any results already executed in remote site.

Abstract: An epitaxial SiC single crystal substrate including a SiC single crystal wafer whose main surface is a c-plane or a surface that inclines a c-plane with an angle of inclination that is more than 0 degree but less than 10 degrees, and SiC epitaxial film that is formed on the main surface of the SiC single crystal wafer, wherein the dislocation array density of threading edge dislocation arrays that are formed in the SiC epitaxial film is 10 arrays/cm2 or less.

Abstract: When processing data via multiple computers, the number of computers can be increased or decreased without actually moving the data assigned to the respective computers, and the data can be arranged and processed so as to enhance the performance of the system in response to the increase of the number of computers. A plurality of computers for performing data processing stores target data to be processed in a shared storage system, and when data processing is to performed, the shared storage divides the storage area storing data corresponding to the number of computers, and creates virtual data storage areas referring to a portion of the storage area for each computer, so as to enable each computer to refer to independent virtual data storage areas and to complete data processing.

Abstract: A storage system comprises a storage apparatus which includes a processor, storage disks, and a memory storing a page mapping table, a page mapping program, and a page-filename mapping program. A file system manages a file tree of files with filenames. The page mapping table specifies a relationship between data volumes in the storage apparatus and the storage disks and the file system, the data volumes each including pages, each page including segments, each segment including sectors. The file tree has for each storage apparatus a hierarchy of directories and files based on relationships among the data volumes, the pages, and the segments. The page mapping program and the page-filename mapping program are executable by the processor to specify, by page, a location of data contained in the I/O request by referring to the page mapping table and the file tree.

Abstract: An aspect of this invention is a computer system, including: a storage apparatus for allocating real storage areas of a plurality of tiers of a tiered real storage area pool to a volume, and migrating and relocating data within the volume between the plurality of tiers; and a host apparatus that accesses the volume provided by the storage apparatus. The host apparatus is configured to refer to tier information including information on a corresponding one of the plurality of tiers to which an access destination address within the volume belongs to identify the corresponding one of the plurality of tiers to which the access destination address belongs and refer to settings predetermined for the plurality of tiers to perform I/O control for the access destination address based on settings of the identified corresponding one of the plurality of tiers.

Abstract: A file storage performs control to create a virtual parent file having an identifier capable of uniquely identifying a parent file among storage systems and volumes, and to acquire block layout information of the parent file using said identifier. The file storage creates a virtual parent file in the volume in which the clone file is created, and sets the file as a virtual parent file of the clone file so as to enable creation of a clone file of a parent file that exists in a different volume or a different storage system. Moreover, by combining creating the virtual parent file and switching the identifier of the parent file which is pointed by the virtual parent file, migration of clone files and parent files astride storage systems and volumes is enabled.

Abstract: In a storage system that includes two or more file servers each including an arbitrary number of operating virtual file servers, a management server: holds a load information table regarding a load on each virtual file server for each time period and redundancy information table for the storage system; judges, with reference to the load information table and redundancy information table, whether or not the loads on the virtual file servers can be handled by a smaller number of file servers than the number of currently-operating file servers; selects, if the judgment result is positive, a power-off target file server and makes another file server fail over a virtual file server in the power-off target file server; and turns off the power-off target file server.

Abstract: Embodiments of the invention provide object-based tier management to improve the allocation of objects to different media of different speeds based on access characteristics such as access frequency. One embodiment is directed to a method of managing object-based data in an information system which includes an application server and a storage system. The method comprises receiving a write command including a first data to be written into a virtual volume; identifying an object to which the first data corresponds; checking if a second data corresponding to the object has been stored in the virtual volume; if the second data has been stored in a page of the virtual volume, checking if the page which stores the second data has a vacancy area; and if the page has a vacancy area, writing the first data in the page which stores the second data.

Abstract: Embodiments of the invention provide methods and systems of managing a file access, in a distributed file system environment. In the provided methods and systems, each of the host computers is connected with one of the file servers as a target file server and issues the file access request to the target file server, for access to a target file stored in at least one of the file servers. The management computer collects load information from the file servers, analyzes it, by specifying location of the target file and the target file server, and based on the analysis, redistributes the target file among the file servers and reallocates connections between the host computers and the target file servers.