Abstract: Provided is a storage system capable of preventing the access performance from a client to a file system from deteriorating even when a file system is migrated among a plurality of file servers. This storage system provided a shared file system having the same namespace to the client accessing the file system. This storage system stores in its memory a first information table storing the correspondence of the file system and the file server mounting the file system, and a second information table storing the correspondence of the file system and the frequency of access by the client to the file system.

Abstract: In a cluster type NAS, it is necessary to copy file data between disk devices of servers upon migration of a file system or a part of the file system. A server includes a control table for managing a file system or a part of the file system, and a mapping table for managing a relation between a logical device of a disk subsystem and a logical unit recognized by a server, and in response to an instruction to execute migration of the file system from a first server to a second server, the mapping table is referenced to send an instruction to update the relation between the logical device and the logical unit to the second server, and the second server newly recognizes a logical unit and updates a management server identifier of the control table.

Abstract: According to one embodiment, a magnetic recording medium includes a protective layer having a plurality of projections on its surface. These projections are formed by forming an etching mask including a mask underlayer and a mask pattern layer having an island structure on the protective layer, and performing dry etching after that.

Abstract: To provide a technique whereby a plurality of types of storage media can be utilized in an efficient manner. A management apparatus includes a file manager that manages files within an integrated memory area that includes a first memory area composed of at least a part of the first type of storage medium and a second memory area composed of at least a part of the second type of storage medium. The file manager builds one filesystem on the integrated memory area, in consideration of a range of the first memory area and a range of the second memory area.

Abstract: The present invention provides a file system capable of reducing time taken to switch I/O paths, and hiding the process of switching the I/O paths from the user. In a system of the present invention in which a file ID is defined for each file, upon receiving a request for accessing a file specifying a file ID from a user, a file server refers to a file management table to obtain a logical disk ID for accessing the file. The file server then refers to a logical disk management table to obtain an I/O path corresponding to the logical disk ID, and accesses a physical disk device by use of the obtained I/O path. When a fault has occurred in an operational I/O path, a file server rewrites the logical disk management tables in all nodes to change the I/O path.

Abstract: In the storage-based snapshot creation, a block-selection specifying unit provided on a NAS processing unit specifies a block, which becomes necessary for the generation of snapshot data, to a specified-block analyzing unit within a disk apparatus. Moreover, a disk controller generates the snapshot data on the block specified as the snapshot target, while making an inquiry to the specified-block analyzing unit. This makes it possible to create the snapshot in a storage-capacity reduced manner, and to specify the snapshot creation in a partition, file, or directory unit.

Abstract: A file server has plural NAS nodes having three processors dispersed in function, a shared cache memory shared between the plural NAS nodes and backed up by a battery, and plural storage devices. A log area for storing data with respect to an access request received by each NAS node is arranged in the shared cache memory. A network processor stores the data with respect to the access request to the log area, and transfers the data of the memory by a DMA at a reading time. Even when a failure is happened in a certain NAS node, another NAS node restores a file system using the log and continues processing to store the data with respect to the access request to the shared cache memory.

Abstract: The redundancy of a file is maintained without using a centralized controller in a system where file servers are connected via a network. Each domain ND within a file storage system includes a file server FS, a monitoring server WS, and a client CL, which are connected via a LAN. When the file server FS detects a failure in another file server FS in the system, it considers that redundancy of a file stored in the failed file server FS has decreased, and then determines whether or not it is responsible for recovering the redundancy. If the file server FS has determined that it is responsible for recovering the redundancy, it selects a file server FS as a file copy source and a file server FS as a file copy destination, and then copies the identical file from the copy source server to the copy destination server.

Abstract: In a distributed file system, when a user requests a computer to create a distributed file, a management computer acquires a list of computers complying with an allocation rule selected by the user from allocation rules taking the performance, security level, reliability level and utility rate into consideration. When the user requests the computer to access the distributed file, on the other hand, the partial files and the server information are collected from each computer. Each computer evaluates the allocation of the partial files based on the selected allocation rule and the server information from each computer, and if required, selects a destination computer and instructs the partial files to be moved to the destination computer.

Abstract: In a system of the present invention in which a file ID is defined for each file, upon receiving a request for accessing a file specifying a file ID from a user, a file server refers to a file management table to obtain a logical disk ID for accessing the file. The file server then refers to a logical disk management table to obtain an I/O path corresponding to the logical disk ID, and accesses a physical disk device by use of the obtained I/O path. When a fault has occurred in an operational I/O path, a file server rewrites the logical disk management tables in all nodes to change the I/O path. This reduces the time taken to switch I/O paths, and hiding the process of switching the I/O paths from the user.

Abstract: In the storage-based snapshot creation, a block-selection specifying unit provided on a NAS processing unit specifies a block, which becomes necessary for the generation of snapshot data, to a specified-block analyzing unit within a disk apparatus. Moreover, a disk controller generates the snapshot data on the block specified as the snapshot target, while making an inquiry to the specified-block analyzing unit. This makes it possible to create the snapshot in a storage-capacity reduced manner, and to specify the snapshot creation in a partition, file, or directory unit.

Abstract: A network attached storage (NAS) system includes a disk array unit equipped with a copy device that copies data, and a NAS processing unit that provides file service via a network and is connected via a communication path to the disk array unit. The NAS processing unit is equipped with a snapshot management device that manages snapshots. The snapshot management device of the NAS processing unit designates a physical block to be copied as a snapshot. The copy device on the disk array unit copies the designated physical block within the disk array unit to create a snapshot and stores the snapshot in a separated region. The snapshot management device of the NAS processing unit manages meta data of the snapshot data in a manner accessible by the user depending on requirements.

Abstract: In order to manage the various types of attribute information within the storage-device system, the storage-device system includes the following databases within a file-access controlling memory: a database for managing index information for managing contents of the files, and an index retrieval program, a database for managing the attribute information on the files, and a database for managing storage positions of blocks configuring a file. When the storage-device system receives an access request to a file, the utilization of these databases allows the storage-device system to make the access to the access-target file.

Abstract: In a distributed file system, when a user requests a computer to create a distributed file, a management computer acquires a list of computers complying with an allocation rule selected by the user from allocation rules taking the performance, security level, reliability level and utility rate into consideration. When the user requests the computer to access the distributed file, on the other hand, the partial files and the server information are collected from each computer. Each computer evaluates the allocation of the partial files based on the selected allocation rule and the server information from each computer, and if required, selects a destination computer and instructs the partial files to be moved to the destination computer.

Abstract: A problem with a journaling file system is that the load on input/output processing executed between a server and a storage system is increased because a journal log is written when the file system is updated and updated data is written when flush processing is executed. In a system according to the present invention, a storage system that has received journal logs from a server uses updated data included in the journal logs to execute flush processing.

Abstract: A computer system in which a host computer is connected to a storage unit, the storage unit operating in a unit of a file. A file attribute control unit and the storage unit execute the processing being linked together so that, in response to a request from a client computer, the host computer executes a file attribute control program to add a particular attribute to the file, and that the storage unit operates in response to the attribute that is added.

Abstract: In order to manage the various types of attribute information within the storage-device system, the storage-device system includes the following databases within a file-access controlling memory: a database for managing index information for managing contents of the files, and an index retrieval program, a database for managing the attribute information on the files, and a database for managing storage positions of blocks configuring a file. When the storage-device system receives an access request to a file, the utilization of these databases allows the storage-device system to make the access to the access-target file.

Abstract: Provided is a storage system as follows. A server holds a management table that serves to manage a mount point of a file system. The management table stores a file system identifier that uniquely identifies the file system within the storage system, mount point information that indicates the mount point of the file system, and a management server identifier that indicates an identifier of the server that manages the file system. The contents stored in the management table of each server are the same. Upon reception of a request to obtain a file handle, each server returns the file handle requested to be obtained. The file handle indicates, uniquely within the storage system, the storage area on the disk subsystem in which the file relating to the request is stored.

Abstract: A problem with a journaling file system is that the load on input/output processing executed between a server and a storage system is increased because a journal log is written when the file system is updated and updated data is written when flush processing is executed. In a system according to the present invention, a storage system that has received journal logs from a server uses updated data included in the journal logs to execute flush processing.

Abstract: When a command received from a client CL is transferred to another server device 100, a server device 100 transfers only the control data part in the command, and exchanges the user data part via a shared memory 200. Because of this, the size of the data that is directly transferred between the server devices 100 is reduced, so it is possible to inhibit delay of responses to the client and to attempt improvement in the performance of the overall storage system. As a result, the processing capability of a storage system having a plurality of server devices is improved.