storage technology foundations glossary

8/8/2019 Storage Technology Foundations Glossary

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Storage Technology Foundations Glossary 4

Item Also KnownAs

Definition RelatedTechnology

connections between IP-based storage devices, hosts and clients.ILM Information

LifecycleManagement

Acronym for data management. Systems

IncrementalBackup

Contains the changes since the last backup, of any type, whichever was most recent. Backup - Restore

Initiators Devices that start a data request. Storage

I/O Channel Input/OutputChannel orRead/WriteChannel

Provides the communication between the I/O Bus and the CPU so that the actualinformation can be recorded on a platter in a hard drive.

Network

Intelligent A device that is controlled by one or more processors integral to the device.

Interoperability The ability of hardware and software made by a variety of different manufacturers to

work seamlessly together.

Systems

JBOD Just a Bunchof Disks

Acronym for disk-based storage. Storage

Latency The time from when the head is over the correct track until the data rotates aroundand is under the head and can be read.

Storage

LBA Logical BlockAddress

A sequential address for accessing blocks on storage media. Storage

Link A connection between two Fibre Channel ports.

LU Logical Unit Devices with SCSI IDs. Systems

LUN Logical UnitNumber

An encoded 3-bit identifier used on an SCSI bus to distinguish among up to eightdevices (logical units) with the same SCSI ID. An LUN is an indivisible unit presentedby a storage device to its host. LUNs are assigned to each disk drive in an array sothe host can address and access the data on those devices.

Storage

LUN Masking An array security feature that lets a server access only its own (and no other) LUNson a Fibre Channel. Each LUN can specify what host or combination of hosts to haveaccess to that LUN.

Network

LVM LogicalVolume

Management

Management of a virtual disk made up of multiple logical disks. Storage

Metadata Data about data. Describes the content, quality, condition, and other characteristicsof data. Also used to identify file characteristics in some file systems.

MTBF Mean TimeBetweenFailure

A statistical calculation that measures average failure rates of devices. Storage

MTTF Mean Timeto Data Loss

A statistical calculation that measures the average time until data loss occurs. Storage

Mirroring A data redundancy technique where all data is written simultaneously to two disk

drives to provide protection against disk failure.

Storage


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Storage Technology Foundations Glossary 7

Item Also KnownAs

Definition RelatedTechnology

Switch A network device that selects a path or circuit for sending a data betweendestinations.

Network

Switched Fabric FC-SW Fibre Channel topology where each device has a unique, dedicated I/O path to thedevice it is communicating with.

SAN

SynchronousOptical Network

SONET A standard for optical telecommunications transport where traffic from multiplesubscribers is multiplexed together and sent out onto a ring as an optical signal.

Network

Target A SCSI device that carries out a request from an initiator.Terabyte TB A thousand billion bytes or one thousand gigabytes. Storage

Throughput In networking, it is a measurement of the amount of data that can be successfullytransferred with a set time period.

Storage

Tracks The concentric rings around disk drive platters where data is written. Storage

Unstructured

Data

Data that is informal, possibly text (such as XML tagged content), disorganized or

stored in files as whole documents or in content management systems.

Storage

Volume A virtual disk into which a file system, database management system or otherapplication places data. A volume can be a single disk partition or multiple partitionson one or more physical drives.

Storage

Wide AreaNetwork

WAN A high-speed network used to connect computers over long distances. Network

Warm Site An alternate processing site which is only partially equipped. Business Continuity

Write-Cache A temporary storage area in memory, where data can be stored before being written

out to disk for permanent storage. This improves system performance.

Storage

Write OnceRead Many

WORM Data written to a storage device (such as an optical disk) that is unchanging but canbe accessed and read many times.

Zoned-bitrecording

A method of recording data that takes advantage of the disks geometry. Storage

Zoning A method of securing data, where hosts are given access to specific storage devices.Hosts can only see and access storage devices within a specified zone.

Storage

storage technology foundations glossary

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