Global Mirror

An optional capability of the DS8000 remote mirror and copy feature that provides a 2-site extended distance remote copy. Data that is written by the host to the storage unit at the local site is automatically maintained at the remote site. See also Metro Mirror and Remote Mirror and Copy.

group In DS8000 documentation, a nickname for two different kinds of groups, depending on the context. See disk pack or Copy Services server group.

H

HA See host adapter.

HACMP

See High-Availability Cluster

Multi-Processing.

hard disk drive (HDD)

1)A storage medium within a storage server used to maintain information that the storage server requires.

2)A mass storage medium for computers that is typically available as a fixed disk (such as the disks used in system units of personal computers or in drives that are external to a personal computer) or a removable cartridge.

hardware service manager (HSM)

An option on an AS/400 or iSeries host that enables the user to display and work with system hardware resources and to debug input-output processors (IOP), input-output adapters (IOA), and devices.

HCD See Hardware Configuration Data.

HDA See head and disk assembly.

HDD See hard disk drive.

hdisk An AIX term for storage space.

head and disk assembly (HDA)

The portion of an HDD associated with the medium and the read/write head.

heartbeat

A status report sent at regular intervals from the DS8000. The service provider uses this report to monitor the health of the call home process. See also call home, heartbeat call home record, and remote technical assistance information network.

heartbeat call home record

Machine operating and service information sent to a service machine. These records might include such information as feature code information and product logical configuration information.

hierarchical storage management

1)A function in storage management software, such as Tivoli Storage Management or Data Facility Storage Management Subsystem/MVS (DFSMS/MVS), that automatically manages free space based on the policy that the storage administrator sets.

2)In AS/400 storage management, an automatic method to manage and distribute data between the different storage layers, such as disk units and tape library devices.

High-Availability Cluster Multi-Processing (HACMP)

Software that provides host clustering, so that a failure of one host is recovered by moving jobs to other hosts within the cluster.

high-speed link (HSL)

A hardware connectivity architecture that links system processors to system input/output buses and other system units.

home address

A nine-byte field at the beginning of a track that contains information that identifies the physical track and its association with a cylinder.

hop Interswitch connection. A hop count is the number of connections that a particular block of data traverses between source and destination. For example, data traveling from one hub over a wire to another hub traverses one hop.

host See host system.

host adapter

A physical subunit of a storage server that provides the ability to attach to one or more host I/O interfaces.

host name

The Internet address of a machine in the network. The host name can be entered in the host definition as the fully qualified domain name of the attached host system, such as mycomputer.city.company.com, or

336IBM TotalStorage DS8000: Messages Reference

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IBM DS8000 manual Global Mirror, Hard disk drive HDD, Hardware service manager HSM, Head and disk assembly HDA, Heartbeat