Abstract: Techniques to assure genuineness of data stored on a storage device are provided. The storage device includes a storage controller that conducts I/O operations and management operations. A description of management operations and corresponding timestamps are recorded to an operation log stored in a memory. The memory additionally stores an attribute for each storage volume of the storage device. Write access to each of the storage volumes is dependent on the attribute.

Abstract: By incorporating a referral mechanism, a failover method and system for remotely mirrored clustered file servers enables a client computer to transparently access a remotely mirrored file system during a failover of a first NAS (network attached storage) storing the file system. The first NAS is clustered with a second NAS that takes over the IP address of the first NAS on failover. A mirroring relationship is established between the first NAS and a third NAS whereby a copy of the file system is replicated to the third NAS. A referral is created on the second NAS, such that an access attempt from the client computer for accessing the first file system that is directed to the second NAS following IP address takeover from the first NAS after failover is referred to the third NAS by the referral to enable the client computer to access the copy of the file system.

Abstract: A method for write protection in a storage system using both the “file-level WORM function” and the “block-level WORM function”. The block-level WORM function has two modes: the first mode is to prohibit both file access and block access, and the second mode is to prohibit block access only. When a user uses the file-level WORM function to prohibit write access to a file in a volume, a file access invokes the first mode of the block-level WORM function to prohibit write access to the volume where the write prohibited file resides.

Abstract: Techniques to assure genuineness of data stored on a storage device are provided. The storage device includes a storage controller that conducts I/O operations and management operations. A description of management operations and corresponding timestamps are recorded to an operation log stored in a memory. The memory additionally stores an attribute for each storage volume of the storage device. Write access to each of the storage volumes is dependent on the attribute.

Abstract: A system for managing clock adjustment in a storage system is provided. The system includes a clock configured to provide a current time, wherein the current time is used to enforce a content retention period, a memory configured to store clock management information, wherein the clock management information includes a last adjustment time and a number of maximum adjustable time ranges, wherein the last adjustment time represents the time which the clock was last adjusted, and a storage access program. The storage access program is configured to receive a proposed new time for the clock, determine whether the proposed new time is reasonable using the current time, the last adjustment time and a specific range selected from the maximum adjustable time ranges, and adjust the current time of the clock to the proposed new time if it is determined that the proposed new time is reasonable.

Abstract: An apparatus, system, and method enable access to a storage system by distinguishing SCSI Object-Based Storage Device Commands (OSD) commands from block-based SCSI commands on the same port and storage subsystem. The storage subsystem has the capability of identifying the storage protocol from a corresponding command, and processes the command accordingly for a storage device formatted for use with the respective storage protocol. This way, a storage subsystem can consolidate data from several dedicated command ports to a single physical port, while also enabling a single storage system to store and provide access to data in multiple different storage protocol formats.

Abstract: A storage system, upon receiving a marker from a host computer, executes a generation determination process for determining a generation of a first logical volume that is used by a host computer, and writes information related to the generation determined in this generation determination process to a physical storage device and/or a memory. A backup controller determines whether or not any data or a specified file and/or folder inside the first logical volume of the immediately preceding generation has changed, and when the result of this determination is affirmative, sends a marker insert indication, which induces the issuance of a marker, to the host computer, and when the result of the determination is negative, does not send the marker insert indication to the host computer.

Abstract: There is a journal area and one or more logical volumes comprising a first logical volume. The journal area is a storage area in which is stored a journal data element, which is a data element that is stored in any storage area of a plurality of storage areas configuring a logical volume, or a data element that is written to the storage area. A controller has a size receiver that receives a write unit size, which is the size of a write data element received from a computer, and a size setting unit that sets the received write unit size in a memory for one or more logical volumes. The size of a journal data element stored in a journal area based on the set write unit size is the write unit size.

Abstract: A first storage system comprises a first logical volume, and a first controller that has a first memory. A second storage system comprises a second physical storage device that constitutes the basis of a second logical volume and a journal area, and a second controller that has a second memory. At least the first memory stores a write unit size, which is the size of a write data element. The journal area is a storage area in which is stored a journal data element, which is a data element that is stored in any block of a plurality of blocks configuring the first and/or second logical volume, or a data element that is written to this block. The size of the journal data element, and the size of the respective blocks that are managed as the respective components of the first and second logical volumes are the write unit size.

Abstract: By incorporating a referral mechanism, a failover method and system for remotely mirrored clustered file servers enables a client computer to transparently access a remotely mirrored file system during a failover of a first NAS (network attached storage) storing the file system. The first NAS is clustered with a second NAS that takes over the IP address of the first NAS on failover. A mirroring relationship is established between the first NAS and a third NAS whereby a copy of the file system is replicated to the third NAS. A referral is created on the second NAS, such that an access attempt from the client computer for accessing the first file system that is directed to the second NAS following IP address takeover from the first NAS after failover is referred to the third NAS by the referral to enable the client computer to access the copy of the file system.

Abstract: One code (a compressed redundant code) is created based on a plurality of first redundant codes, each created on the basis of a plurality of data units, and this compressed redundant code is written to a nonvolatile storage area. This compressed redundant code is used to restore either a data element constituting a multiple-failure data, or a first redundant code corresponding to the multiple-failure data, which is stored in an unreadable sub-storage area of a partially failed storage device, and to restore the data element constituting the multiple-failure data which is stored in a sub-storage area of a completely failed storage device, based on the restored either data element or first redundant code, and either another data element constituting the multiple-failure data or the first redundant code corresponding to the multiple-failure data.

Abstract: In a storage system, a server apparatus and a storage apparatus are provided, while the server apparatus is connected via a LAN to one, or plural sets of computers so as to accept an access request of file data issued from the computers, whereas the storage apparatus is connected via a wide area network to the server apparatus so as to store thereinto the file data. A communication between the computers and the server apparatus is carried out by employing a network file protocol, whereas a communication between the server apparatus and the storage apparatus is performed by employing a block device protocol. The server apparatus and the storage apparatus are connected via the respective security protecting apparatus to the wide area network.

Abstract: In the remote mirroring system of this invention, the primary system has the capability of treating the volume in the remote storage system as a virtual storage devices in the primary storage system. The primary storage system realizes remote mirroring between different storage systems by copying data from the primary volume to the virtual volume(s) defined in the primary storage system. This enables remote mirroring between storage systems produced by the different vendors.

Abstract: A volume provider unit in a computer system that detects a logical block address of a read or write I/O accessing a logical volume of a storage device from a host. According to the logical block address fetched, a storage domain of the logical volume is dynamically expanded. Moreover, the storage domain of the logical volume is reduced or expanded according to an instruction of logical volume capacity reduction or expansion from a host commander part to a volume server.

Abstract: An information system includes a primary storage system (PSS), a host, an external storage system (ESS), and a management host. The PSS uses virtual devices to treat logical devices in the ESS as if they were logical devices in the PSS. The ESS logical devices are configured using multiple disks for providing redundancy, such as in a RAID configuration, to enable migration of data following hardware failure in the ESS. When a disk forming part of an ESS logical device fails, the management host detects the failure and judges whether the ESS logical device is used by the PSS to form a virtual device. If the ESS logical device is used to form a virtual device, then the management host issues a migration request. In response to the migration request, the PSS migrates data from the ESS logical device to a logical device in the PSS to avoid data loss.

Abstract: A storage device system comprises interfaces connected to computers, a plurality of magnetic disks, and a control device that controls the plurality of magnetic disks. When a command from one of the computers instructing a tape library device to load a magnetic tape into a tape device is received by one of the interfaces, the control device selects a storage region that is managed as a virtual tape from among storage regions of the magnetic disks. When one of the interfaces receives an access request from the computer to the tape device, the control device controls to access the storage region selected.

Abstract: Data of a global file system spread over multiple local NAS systems may be consolidated as a copy into a single remote NAS system. When remote copy is set up, the local NAS systems replace referrals within the global file system with directories and send these in place of the referrals to the remote NAS system. Then, other local NAS systems referred to by the referrals send files and directories under the directories replacing the referrals on the remote NAS system. Alternatively, to split copy data of a locally-stored global file system amongst multiple remote NAS systems, the local NAS system replaces specified directories with referrals, and sends the referrals with the data to one of the remote NAS systems. Then, the local NAS system sends files and directories under the directories replaced with referrals to one or more other remote NAS systems as referred to by the referrals.

Abstract: A storage system comprises a primary storage system comprising a primary storage apparatus and a primary control apparatus for controlling the primary storage apparatus; and a secondary storage system comprising a secondary storage apparatus and secondary control apparatus for controlling the secondary storage apparatus. The primary storage apparatus and the secondary storage apparatus are connected to each other via a communication line. The primary storage system sends, to the primary storage apparatus, a data-transfer instruction instructing the primary storage apparatus to transfer predetermined data stored in the primary storage apparatus to the secondary storage system. The primary storage apparatus receives the data-transfer instruction, reads out the predetermined data from the primary storage apparatus, and sends the data via the communication line to the secondary storage apparatus of the secondary storage system.

Abstract: A storage system 1 including multiple slots for loading a block I/O interface controller, a file I/O interface controller, and any other kinds of interface controllers that are combined freely. The storage system 1 includes a management table that manages fail-over-enabled devices by grouping those devices in accordance with the interface type and the domain to which each device belongs; an information table that directs a fail-over procedure; and fail-over controlling means that takes over the processing of a failed interface controller belonging to a fail-over-enabled group. The fail-over system offers several modalities for monitoring failures, selecting takeover controllers and restoring functionality. Storage system 1 solves conventional problems by providing a system that can mount a plurality of file systems, and that resists multiple failures detected in a fail-over server.

Abstract: A volume provider unit in a computer system that detects a logical block address of a read or write I/O accessing a logical volume of a storage device from a host. According to the logical block address fetched, a storage domain of the logical volume is dynamically expanded. Moreover, the storage domain of the logical volume is reduced or expanded according to an instruction of logical volume capacity reduction or expansion from a host commander part to a volume server.