Oracle HSM Glossary

Version 2

    Oracle HSM Glossary

    For storage industry standard definitions, see http://www.snia.org/education/dictionary/.

    TermDefinition
    addressable storageThe storage space encompassing online, nearline, offsite, and offline storage that is user-referenced through a Sun QFS file system.
    archive mediaThe media to which an archive file is written. Archive media can be removable tape or magneto-optical cartridges in a library. In addition, archive media can be a mount point on another system.
    archive setAn archive set identifies a group of files to be archived, and the files share common criteria that pertain to the size, ownership, group, or directory location. Archive sets can be defined across any group of file systems.
    archive storageCopies of file data that have been created on archive media.
    archiverThe archive program that automatically controls the copying of files to removable cartridges.
    audit (full)The process of loading cartridges to verify their VSNs. For magneto-optical cartridges, the capacity and space information is determined and entered into the automated library's catalog. See also, VSN.
    automated libraryA robotically controlled device designed to automatically load and unload removable media cartridges without operator intervention. An automated library contains one or more drives and a transport mechanism that moves cartridges to and from the storage slots and the drives.
    backup storageA snapshot of a collection of files for the purpose of preventing inadvertent loss. A backup includes both the file's attributes and associated data.
    block allocation mapA bitmap representing each available block of storage on a disk and indicating whether the block is in use or free.
    block sizeSee DAU.
    cartridgeA physical entity that contains media for recording data, such as a tape or optical disk. Sometimes referred to as a piece of media, a volume, or the medium.
    catalogA record of the VSNs in an automated library. There is one catalog for each automated library and, at a site, there is one historian for all automated libraries. See also, VSN.
    client-serverThe model of interaction in a distributed system in which a program at one site sends a request to a program at another site and awaits a response. The requesting program is called the client. The program satisfying the response is called the server.
    connectionThe path between two protocol modules that provides reliable stream delivery service. A TCP connection extends from a TCP module on one machine to a TCP module on the other.
    data deviceIn a file system, a device or group of devices upon which file data is stored.
    DAUDisk allocation unit. The basic unit of online storage. Also called block size.
    device loggingA configurable feature that provides device-specific error information used to analyze device problems.
    device scannerSoftware that periodically monitors the presence of all manually mounted removable devices and that detects the presence of mounted cartridges that can be requested by a user or other process.
    direct accessA file attribute (stage never) designating that a nearline file can be accessed directly from the archive media and need not be retrieved to disk cache.
    direct attached libraryAn automated library connected directly to a server using a SCSI interface. A SCSI-attached library is controlled directly by the Sun Storage Archive Manager software.
    direct I/OAn attribute used for large block-aligned sequential I/O. The setfa(1) command's -D option is the direct I/O option. It sets the direct I/O attribute for a file or directory. If applied to a directory, the direct I/O attribute is inherited.
    directoryA file data structure that points to other files and directories within the file system.
    disk allocation unitSee DAU.
    disk bufferIn a Sun SAM-Remote configuration, the buffer on the server system that is used for archiving data from the client to the server.
    disk cacheThe disk-resident portion of the file system software, used to create and manage data files between online disk cache and archive media. Individual disk partitions or an entire disk can be used as disk cache.
    disk space thresholdThe maximum or minimum level of disk cache utilization, as defined by an administrator. The releaser controls disk cache utilization based on these predefined disk space thresholds.
    disk stripingThe process of recording a file across several disks, thereby improving access performance and increasing overall storage capacity. See also striping.
    driveA mechanism for transferring data to and from a removable media volume.
    EthernetA local-area, packet-switched network technology. Originally designed for coaxial cable, it is now found running over shielded, twisted-pair cable. Ethernet is a 10- or 100-Mbytes/second LAN.
    extent arrayThe array within a file’s inode that defines the disk location of each data block assigned to the file.
    family device setSee family set.
    family setA storage device that is represented by a group of independent physical devices, such as a collection of disks or the drives within an automated library. See also storage family set.
    FDDIFiber-distributed data interface (FDDI) is a standard for data transmission in a local area network that can extend in range up to 200 km (124 miles). The FDDI protocol is based on the token ring protocol.
    Fibre ChannelThe ANSI standard that specifies high-speed serial communication between devices. Fibre Channel is used as one of the bus architectures in SCSI-3.
    file systemA hierarchical collection of files and directories.
    file-system-specific directivesArchiver and releaser directives that follow global directives in the archiver.cmd file, are specific to a particular file system, and begin with fs =. File-system-specific directives apply until the next fs = directive line or the end of file is encountered. If multiple directives affect a file system, the file-system-specific directives override the global directives.
    FTPFile transfer protocol. An Internet protocol for transferring files between two hosts over a TCP/IP network.
    global directivesArchiver and releaser directives that apply to all file systems and that appear before the first fs = line.
    grace periodFor disk quotas, the amount of time for which a user is allowed to create files and allocate storage after reaching the soft limit.
    hard limitFor disk quotas, the maximum limit on file system resources, blocks, and inodes that users cannot exceed.
    hosts fileThe hosts file contains a list of all of the hosts in a shared file system. If you are initializing a file system as a Sun QFS shared file system, the hosts file, /etc/opt/SUNWsamfs/hosts.fs-name, must be created before the file system is created. The sammkfs(1M) command uses the hosts file when it creates the file system. You can use the samsharefs(1M) command to replace or update the contents of the hosts file at a later date.
    indirect blockA disk block that contains a list of storage blocks. File systems have up to three levels of indirect blocks. A first-level indirect block contains a list of blocks used for data storage. A second-level indirect block contains a list of first-level indirect blocks. A third-level indirect block contains a list of second-level indirect blocks.
    inodeIndex node. A data structure used by the file system to describe a file. An inode describes all the attributes associated with a file other than the name. The attributes include ownership, access, permission, size, and the file location on the disk system.
    inode fileA special file (.inodes) on the file system that contains the inode structures for all files resident in the file system. Inodes are 512 bytes long. The inode file is a metadata file, which is separated from file data in the file system.
    kernelThe central controlling program that provides basic system facilities. The UNIX kernel creates and manages processes, provides functions to access the file system, provides general security, and supplies communication facilities.
    LANLocal area network.
    leaseA function that grants a client host permission to perform an operation on a file for a specified period of time. The metadata server issues leases to each client host. The leases are renewed as necessary to permit continued file operations.
    librarySee automated library.
    library catalogSee catalog.
    local file systemA file system that is installed on one node of a Sun Cluster system and is not made highly available to another node. Also, a file system that is installed on a server.
    LUNLogical unit number.
    mcfMaster configuration file. The file that is read at initialization time that defines the relationships between the devices (the topology) in a file system environment.
    mediaTape or optical disk cartridges.
    media recyclingThe process of recycling or reusing archive media with few active files.
    metadataData about data. Metadata is the index information used to locate the exact data position of a file on a disk. It consists of information about files, directories, access control lists, symbolic links, removable media, segmented files, and the indexes of segmented files.
    metadata deviceA device (for example, a solid-state disk or mirrored device) upon which file system metadata is stored. Having file data and metadata on separate devices can increase performance. In the mcf file, a metadata device is declared as an mm device within an ma file system.
    mirror writingThe process of maintaining two copies of a file on disjointed sets of disks to prevent loss from a single disk failure.
    mount pointThe directory on which a file system is mounted.
    multireader file systemA single-writer, multireader capability that enables you to specify a file system that can be mounted on multiple hosts. Multiple hosts can read the file system, but only one host can write to the file system. Multiple readers are specified with the -o reader option with the mount(1M) command. The single-writer host is specified with the -o writer option with the mount(1M) command. For more information on the mount(1M) command, see the mount_samfs(1M) man page.
    name spaceThe metadata portion of a collection of files that identifies the file, its attributes, and its storage locations.
    nearline storageRemovable media storage that requires robotic mounting before it can be accessed. Nearline storage is usually less expensive than online storage, but it takes somewhat longer to access.
    network attached automated libraryA library, such as those from StorageTek, ADIC/Grau, IBM, or Sony, that is controlled using a software package supplied by the vendor. The QFS file system interfaces with the vendor software using a Sun Storage Archive Manager media changer daemon designed specifically for the automated library.
    NFSNetwork file system. A file system distributed by Sun that provides transparent access to remote file systems on heterogeneous networks.
    NISThe Sun OS 4.0 (minimum) Network Information Service. A distributed network database containing key information about systems and users on the network. The NIS database is stored on the master server and all slave servers.
    offline storageStorage that requires operator intervention for loading.
    offsite storageStorage that is remote from the server and is used for disaster recovery.
    online storageStorage that is immediately available, such as disk cache storage.
    Oracle HSMA configuration that combines the Storage Archive Manager software with the StorageTek QFS file system. This configuration enables you to archive file system data by combining a high-speed, standard UNIX file system interface with the storage and archive management utilities. Previously marketed as the SAM-QFS file system, beginning with release 6.0, Oracle HSM includes the QFS file system.
    partitionA portion of a device or a side of a magneto-optical cartridge.
    preallocationThe process of reserving a contiguous amount of space on the disk cache for writing a file. Preallocation can be specified only for a file that is size zero. For more information, see the setfa(1) man page.
    pseudo deviceA software subsystem or driver with no associated hardware.
    QFSThe file system features of Oracle HSM. A QFS file system can be used separately from the Sun Storage Archive Manager archiving features.
    quotaThe amount of system resources that a user is allowed to consume.
    RAIDRedundant array of independent disks. A disk technology that uses several independent disks to reliably store files. It can protect against data loss from a single disk failure, can provide a fault-tolerant disk environment, and can provide higher throughput than individual disks.
    recyclerA Sun Storage Archive Manager utility that reclaims space on cartridges that is occupied by expired archive copies.
    release priorityThe priority according to which a file in a file system is released after being archived. Release priority is calculated by multiplication of various weights of file properties and then summation of the results.
    releaserA Sun Storage Archive Manager component that identifies archived files and releases their disk cache copies, thus making more disk cache space available. The releaser automatically regulates the amount of online disk storage according to high and low thresholds.
    remote procedure callSee RPC.
    removable media fileA special type of user file that can be accessed directly from where it resides on a removable media cartridge, such as magnetic tape or optical disk cartridge. Also used for writing archive and stage file data.
    robotThe portion of an automated library that moves cartridges between storage slots and drives. Also called a transport.
    round-robinA data access method in which entire files are written to logical disks in a sequential fashion. When a single file is written to disk, the entire file is written to the first logical disk. The second file is written to the next logical disk, and so on. The size of each file determines the size of the I/O.
    See also disk striping and striping.
    RPCRemote procedure call. The underlying data exchange mechanism used by NFS to implement custom network data servers.
    SAMSee Oracle HSM.
    SAM-QFSFormer name of Oracle HSM up to version 5.4.  See Oracle HSM.
    samfsdumpA program that creates a control structure dump and copies all the control structure information for a given group of files. It is analogous to the UNIX tar(1) utility, but it does not generally copy file data. See also samfsrestore.
    samfsrestoreA program that restores inode and directory information from a control structure dump. See also samfsdump.
    SCSISmall Computer System Interface. An electrical communication specification commonly used for peripheral devices such as disk and tape drives and automated libraries.
    shared hosts fileWhen you create a shared file system, the system copies information from the hosts file to the shared hosts file on the metadata server. You update this information when you issue the samsharefs(1M) -u command
    Small Computer System InterfaceSee SCSI.
    soft limitFor disk quotas, a threshold limit on file system resources (blocks and inodes) that you can temporarily exceed. Exceeding the soft limit starts a timer. When you exceed the soft limit for the specified time, no further system resources can be allocated until you reduce file system use to a level below the soft limit.
    stagingThe process of copying a nearline or offline file from archive storage back to online storage.
    storage family setA set of disks that are collectively represented by a single disk family device.
    storage slotsLocations inside an automated library in which cartridges are stored when not being used in a drive.
    stripe sizeThe number of disk allocation units (DAUs) to be allocated before writing proceeds to the next device of a stripe. If the stripe=0 mount option is used, the file system uses round-robin access, not striped access.
    striped groupA collection of devices within a file system that is defined in the mcf file as one or more gXXX devices. Striped groups are treated as one logical device and are always striped with a size equal to the disk allocation unit (DAU).
    stripingA data access method in which files are simultaneously written to logical disks in an interlaced fashion. SAM-QFS file systems provide two types of striping: “hard striping,” using stripe groups, and “soft striping,” using the stripe=x mount parameter. Hard striping is enabled when a file system is set up, and requires the definition of stripe groups within the mcf file. Soft striping is enabled through the stripe=x mount parameter, and can be changed for the file system or for individual files. It is disabled by setting stripe=0. Hard and soft striping can both be used if a file system is composed of multiple stripe groups with the same number of elements. See also round-robin.
    Sun SAM-Remote clientA Sun Storage Archive Manager system with a client daemon that contains a number of pseudodevices, and can also have its own library devices. The client depends on a Sun SAM-Remote server for archive media for one or more archive copies.
    Sun SAM-Remote serverBoth a full-capacity Sun Storage Archive Manager storage management server and a Sun SAM-Remote server daemon that defines libraries to be shared among Sun SAM-Remote clients.
    superblockA data structure in the file system that defines the basic parameters of the file system. The superblock is written to all partitions in the storage family set and identifies the partition’s membership in the set.
    tarTape archive. A standard file and data recording format used for archive images.
    TCP/IPTransmission Control Protocol/Internet Protocol. The internet protocols responsible for host-to-host addressing and routing, packet delivery (IP), and reliable delivery of data between application points (TCP).
    timerQuota software that keeps track of the period starting when a user reaches a soft limit and ending when the hard limit is imposed on the user.
    vfstab fileThe vfstab file contains mount options for the file system. Mount options specified on the command line override those specified in the /etc/vfstab file, but mount options specified in the /etc/vfstab file override those specified in the samfs.cmd file.
    volumeA named area on a cartridge for sharing data. A cartridge has one or more volumes. Double-sided cartridges have two volumes, one on each side.
    volume overflowA capability that enables the system to span a single file over multiple volumes. Volume overflow is useful for sites using very large files that exceed the capacity of their individual cartridges.
    VSNVolume serial name. In the context of archiving to removable media cartridges, the VSN is a logical identifier for magnetic tape and optical disk that is written in the volume label. In the context of archiving to disk cache, this is the unique name for the disk archive set.
    WORMWrite once read many. A storage classification for media that can be written only once but read many times.