longwave laser adapter

A connector that is used between a host and the DS8000 to support longwave fibre-channel communication.

loop The physical connection between a pair of device adapters in the DS8000. See also device adapter.

LPAR See logical partition.

LRC See longitudinal redundancy check. LRU See least recently used.

LSS See logical subsystem.

LUN See logical unit number.

LVM See logical volume manager.

M

machine level control (MLC)

A database that contains the EC level and configuration of products in the field.

machine reported product data (MRPD) Product data gathered by a machine and sent to a destination such as an IBM support server or RETAIN. These records might include such information as feature code information and product logical configuration information.

mainframe

A computer, usually in a computer center, with extensive capabilities and resources to which other computers may be connected so that they can share facilities.

(T)

maintenance analysis procedure (MAP)

A hardware maintenance document that gives an IBM service representative a step-by-step procedure for tracing a symptom to the cause of a failure.

management console

See IBM TotalStorage Management

Console.

Management Information Base (MIB)

1)A collection of objects that can be accessed by means of a network management protocol. (GC)

2)The MIB record conforms to the Open Systems Interconnection (OSI) standard defined by the International Organization for Standardization (ISO) for the exchange of information. See also simple network management protocol.

MAP See maintenance analysis procedure.

master storage unit

The physical unit that controls the creation of consistency groups in a Global Mirror session. The master storage unit sends commands to subordinate storage units. A storage unit can be a master for only one Global Mirror session. Contrast with subordinate storage unit.

maximum consistency group drain time The value in seconds that indicates the maximum time that writes from the local site are delayed to the remote site while the current consistency group is being formed at the remote site. When this time is exceeded, the current attempt to form a consistency group is ended and another attempt is started. If this time is exceeded five times, this maximum time is ignored on the next attempt to form a consistency group. The default value is the larger of four minutes or two times the consistency group interval time if this value is set to zero.

maximum coordination time

The value in milliseconds that indicates the maximum time that is allowed for host I/O to be delayed during the coordination of the primary volumes of an Global Mirror session. The default is 50 milliseconds if this value is set to zero.

MB See megabyte.

MC See IBM TotalStorage Management Console.

MCA See Micro Channel architecture. MDM See Multiple Device Manager. mean time between failures (MTBF)

1)A projection of the time that an individual unit remains functional. The time is based on averaging the performance, or projected performance, of a population of statistically independent units. The units operate under a set of conditions or assumptions.

2)For a stated period in the life of a functional unit, the mean value of the lengths of time between consecutive failures under stated conditions. (I) (A)

medium

For a storage unit, the disk surface on which data is stored.

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IBM DS8000 manual Longwave laser adapter, Machine level control MLC, Maintenance analysis procedure MAP, Management console