US Robotics 7931 Podręcznik Użytkownika Pobierz pdf (Strona 275)

Glossary 251

SAM-QFS A configuration that combines the Sun StorageTek SAM software with the Sun

StorageTek QFS file system. SAM-QFS offers a high-speed, standard UNIX file

system interface to users and administrators in conjunction with the storage

and archive management utilities. It uses many of the commands available in

the Sun StorageTek SAM command set as well as standard UNIX file system

commands.

samfsrestore A program that restores inode and directory information from a control

structure dump. See also samfsdump.

SCSI Small Computer System Interface. An electrical communication specification

commonly used for peripheral devices such as disk and tape drives and

automated libraries.

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(1M) -u command

Small Computer

System Interface See SCSI.

soft limit For 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.

staging The process of copying a nearline or offline file from archive storage back to

online storage.

storage family set A set of disks that are collectively represented by a single disk family device.

storage slots Locations inside an automated library in which cartridges are stored when not

being used in a drive.

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).

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.

striping A 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.

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US Robotics 7931 Podręcznik Użytkownika Strona 275