| Oracle® Hierarchical Storage Manager and StorageTek QFS Software Installation and Configuration Guide Release 6.0 E78137-01 |
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| Oracle® Hierarchical Storage Manager and StorageTek QFS Software Installation and Configuration Guide Release 6.0 E78137-01 |
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This glossary focuses on terms specific to Oracle HSM software and file systems. For industry standard definitions, please refer to the dictionary maintained by the Storage Networking Industry Association at http://www.snia.org/education/dictionary/.
addressable storage
The storage space encompassing online, nearline, offsite, and offline storage that is user-referenced through an Oracle HSM file system.
admin set ID
A storage administrator-defined set of users and/or groups that share common characteristics. Admin sets are typically created to administer storage for projects that involve users from several groups and span multiple files and directories.
archival media
The media to which an archive file is written. Archival media includes both removable tape or magneto-optical cartridges and disk file systems configured for archiving.
archive set
An 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.
archiver
The archive program that automatically controls the copying of files to removable cartridges.
associative staging
Staging a group of related files when any one member of the group is staged. When files inhabit the same directory and are frequently used together, file owners can associate them by setting the Oracle HSM associative-staging file attribute. Then if any files in the group are offline when one of them is accessed by an application, Oracle HSM stages the entire group from archival media to disk cache. This insures that all needed files re available at the same time.
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 volume serial number (VSN).
automated library
A 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
A 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 map
A bitmap representing each available block of storage on a disk and indicating whether the block is in use or free.
block size
The size of the smallest addressable data unit on a block device, such as a hard disk or magnetic tape cartridge. On disk devices, this is equivalent to the sector size, which is typically 512 bytes.
cartridge
A container for data-storage media, such as magnetic tape or optical media. Also called a volume, tape, or piece of media. See volume serial number (VSN).
catalog
A record of the removable media volumes in an automated library. There is one catalog for each automated library and, at a site, there is one historian for all automated libraries. Volumes are identified and tracked using a volume serial number (VSN).
client-server
The 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.
connection
The 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.
device logging
A configurable feature that provides specific error information for the hardware devices that support a Oracle HSM file system.
device scanner
Software 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 access
A 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 library
An automated library connected directly to a server using a SCSI interface. A SCSI-attached library is controlled directly by the Oracle HSM software.
direct I/O
An attribute used for large block-aligned sequential I/O. The setfa 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.
disk allocation unit (DAU)
In Oracle HSM file systems, the minimum amount of contiguous space that each I/O operation consumes, regardless of the amount of data written. The disk allocation unit thus determines minimum number of I/O operations needed when transferring a file of a given size. It should be a multiple of the block size of the disk device.
Disk allocation unit vary depending upon the Oracle HSM device type selected and user requirements. The md device type uses dual-allocation units: the DAU is 4 kilobytes for the first eight writes to a file and then a user-specified 16, 32, or 64 kilobytes for any subsequent writes, so that small files are written in suitably small blocks, while larger files are written in larger blocks. The mr and striped group device types use a DAU that is adjustable in increments of 8 within the range [8-65528] kilobytes. Files are thus written in large, uniform blocks that can closely approximate the size of the large, uniformly sized files.
disk buffer
In a SAM-Remote configuration, the buffer on the server system that is used for archiving data from the client to the server.
disk cache
The 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 threshold
The 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 striping
The process of recording a file across several disks, thereby improving access performance and increasing overall storage capacity. See also striping.
extent array
The array within a file's inode that defines the disk location of each data block assigned to the file.
family set
A logical grouping of independent physical devices, such as a collection of disks or the drives within an automated library. See also storage family set.
FDDI
Fiber-distributed data interface, 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 Channel
The ANSI standard that specifies high-speed serial communication between devices. Fibre Channel is used as one of the bus architectures in SCSI-3.
file-system-specific directives
Archiver 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.
ftp
File Transfer Protocol, a network protocol for transferring files between two hosts. For a more secure alternative, see sftp.
global directives
Archiver and releaser directives that apply to all file systems and that appear before the first fs= line.
grace period
In a quota, the amount of time that the file system allows the total size of files belonging to specified user, group, and/or admin set IDs to exceed the soft limit specified in the quota.
hard limit
In a quota, the absolute maximum quantity of storage resources that specified user, group, and/or admin set IDs can consume. See soft limit.
high-water mark
In an archiving file system, the percentage disk-cache utilization at which Oracle HSM file systems start the releaser process, deleting previously archived files from disk. A properly configured high-water mark insures that the file system always has enough space available for new and newly staged files. For more information, see the sam-releaser and mount_samfs man pages. Compare low-water mark.
In a removable media library that is part of an archiving file system, the percentage media-cache utilization that starts the recycler process. Recycling empties partially full volumes of current data so that they can replaced by new media or relabeled.
historian
The Oracle HSM historian is a catalog of volumes that have been exported from automated media libraries that are defined in the /etc/opt/SUNWsamfs/mcf file. By default, it is located on the Oracle HSM file-system host at /var/opt/SUNWsamfs/catalog/historian. For details, see the Oracle HSM historian man page.
hosts file
The hosts file contains a list of all of the hosts in a shared file system. If you are initializing a file system as a Oracle HSM shared file system, the hosts file, /etc/opt/SUNWsamfs/hosts.fs-name, must be created before the file system is created. The sammkfs command uses the hosts file when it creates the file system. You can use the samsharefs command to replace or update the contents of the hosts file at a later date.
indirect block
A 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.
inode
Index 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 file
A 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.
kernel
The program that provides basic operating system facilities. The UNIX kernel creates and manages processes, provides functions to access the file system, provides general security, and supplies communication facilities.
lease
A 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.
local file system
A file system that is installed on one node of a Solaris Cluster system and is not made highly available to another node. Also, a file system that is installed on a server.
low-water mark
In an archiving file system, the percentage disk-cache utilization at which Oracle HSM file systems stops the releaser process and stops deleting previously archived files from disk. A properly configured low-water mark insures that the file system retains as many file in cache as possible, for best performance, while making space available for new and newly staged files. For more information, see the sam-releaser and mount_samfs man pages. Compare high-water mark.
mcf
Master Configuration File. The file that is read at initialization time that defines the relationships between the devices (the topology) in a file system environment.
metadata
Data 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 device
A 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 writing
The process of maintaining two copies of a file on disjointed sets of disks to prevent loss from a single disk failure.
multireader file system
A 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 command. The single-writer host is specified with the -o writer option with the mount command. For more information, see the mount_samfs man page.
name space
The metadata portion of a collection of files that identifies the file, its attributes, and its storage locations.
nearline storage
Removable 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 library
A 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 Oracle HSM media changer daemon designed specifically for the automated library.
NFS
Network file system, a file system that provides transparent access to remote file systems on heterogeneous networks.
NIS
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.
Oracle HSM
A common abbreviation for Oracle Hierarchical Storage Manager.
An adjective describing a QFS file system that is configured for archiving and managed by Oracle HSM software.
preallocation
The 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 man page.
QFS
The Oracle HSM QFS Software product, a high-performance, high-capacity, UNIX file system that can be used on its own or as an archiving file system controlled by Oracle Hierarchical Storage Manager.
quota
The amount of storage resources that specified user, group, or admin set IDs are allowed to consume. See hard limit and soft limit.
RAID
Redundant 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.
recovery point
A compressed file that stores a point-in-time backup copy of the metadata for a Oracle HSM file system.
In the event of a data loss—anything from accidental deletion of a user file to catastrophic loss of a whole file system—an administrator can recover to the last known-good state of the file or file system almost immediately by locating the last recovery point at which the file or file system remained intact. The administrator then restores the metadata recorded at that time and either stages the files indicated in the metadata to the disk cache from archival media or, preferably, lets the file system stage files on demand, as users and applications access them.
recycler
A Oracle HSM utility that reclaims space on cartridges that is occupied by expired archive copies.
regular expression
A string of characters in a standardized pattern-matching language that is designed for searching, selecting, and editing other character strings, such as file names and configuration files. For full details of the regular expression syntax used in Oracle HSM file-system operations, see the Oracle HSM Solaris regex and regcmp man pages.
release priority
The 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.
releaser
A Oracle HSM 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.
removable media file
A 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.
robot
An automated library component that moves cartridges between storage slots and drives. Also called a transport.
round-robin
A 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.
RPC
Remote procedure call. The underlying data exchange mechanism used by NFS to implement custom network data servers.
SAM
A common abbreviation for Storage Archive Manager, the former name of the Oracle Hierarchical Storage Manager product.
SAM-Remote client
An Oracle HSM system with a client daemon that contains a number of pseudodevices, and can also have its own library devices. The client depends on a SAM-Remote server for archive media for one or more archive copies.
SAM-Remote server
Both a full-capacity Oracle HSM storage management server and a SAM-Remote server daemon that defines libraries to be shared among SAM-Remote clients.
SAM-QFS
A common abbreviation for older versions of the Oracle Hierarchical Storage Manager product.
An adjective describing a QFS file system that is configured for archiving and managed by Oracle HSM software.
samfsdump (qfsdump)
A program that creates a control structure dump and copies all the control structure information for a given group of files. It does not generally copy file data. With the -U option, the command also copies data files. If the Oracle Hierarchical Storage Manager packages are not installed, the command is called qfsdump.
samfsrestore (qfsrestore)
A program that restores inode and directory information from a control structure dump. See also samfsdump (qfsdump).
SCSI
Small Computer System Interface, an electrical communication specification commonly used for peripheral devices such as disk and tape drives and automated libraries.
seeking
Moving the read/write heads of a disk device from one disk location to another during random-access I/O operations.
shared hosts file
When 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 -u command
soft limit
In a quota, the maximum amount of storage space that a specified user, group, and/or admin set IDs can fill for an indefinite period. Files can use more space than the soft limit allows, up to the hard limit, but only for a short grace period defined in the quota. See hard limit.
ssh
Secure Shell, an encrypted network protocol that allows secure, remote command-line login and command execution.
staging
The process of copying a nearline or offline file from archive storage back to online storage.
storage slots
Locations inside an automated library in which cartridges are stored when not being used in a drive.
stripe size
The 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 group
A 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).
striping
A data access method in which files are simultaneously written to logical disks in an interlaced fashion. Oracle HSM 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.
SUNW.qfs
A Solaris Cluster resource type that supports Oracle HSM shared file systems. The SUNW.qfs resource type defines failover resources for the shared file system's metadata server (MDS)
superblock
A 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.
TCP/IP
Transmission 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).
timer
Quota 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 file
The 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.
volume
On storage media, a single, accessible, logical storage area, usually addressed by a volume serial number (VSN) and/or volume label. Storage disks and magnetic tape cartridges can hold one or more volumes. For use, volumes are mounted on a file system at a specified mount point.
A magnetic tape cartridge that holds a single logical volume.
On a random-access disk device, a file system, directory or file that is configured and used as if it were a sequential-access, removable-media cartridge, such as a tape.
volume overflow
A 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.
volume serial number (VSN)
A serial number assigned to a tape or disk storage volume. A volume serial number can consist of up to six uppercase, alphanumeric characters, must start with a letter, and must identify the volume uniquely within a given context, such a tape library or partition. The volume serial number is written on the volume label.
Loosely, a specific storage volume, especially a removable media cartridge.
