15.10 - About Channel Connections to the Database - Teradata Tools and Utilities

Teradata Tools and Utilities for IBM z/OS Installation Guide

Teradata Tools and Utilities
August 2016

If any channel communication is used to access the Teradata Database, devices for one or more Channel Processors must be added to the MVS I/O configuration. Only Channel Processors (CP) are defined to the z/OS system. Other Teradata server hardware and peripherals are not.

All CPs for one TDP must be associated with the same logical host id, which is defined using the Configuration Utility (described in Support Utilities, B035-1180) specifying a Host Type Designator of 'IBM'. CPs are associated with a logical host using the Teradata Database Parallel Upgrade Tool, described by the 'Parallel Upgrade Tool (PUT)' document appropriate to the Database operating system. PUT refers to CPs as 'MF Channel connections'. When multiple Teradata Databases have logical host ids with CPs accessed by TDPs in the same MVS image, all these Logical-host ids must be unique.

Device Connection

Devices are connected to the client through a channel. Each CP is identified by a pair of consecutive even-odd device numbers. The first number, for the output device, must be even (low-order bit = 0). The second, for the input device, must be odd (low-order bit = 1).

A Teradata device:
  • Is dedicated to a single TDP through a single channel interface
  • Can be online to only one z/OS system at a time
  • Does not support multiple channel connections
  • Can be used by different TDPs at different times

The physical implementation of a Teradata device may vary in different Teradata servers. Each physical processor has a single channel interface that provides the only channel interface for all device pairs associated with that processor.

When defining the I/O configurations, a CP is effectively a control unit that has one input and one output device associated with it. Physical implementation examples include the following:
  • One physical processor implements a single pair of devices
  • One physical processor implements multiple pairs of devices

Physical Connection

There are two types of physical connections to a Teradata server:
  • Enterprise Systems Connection (ESCON)
  • Fibre-channel Connection (FICON)

Each FICON Bridge supports up to eight different ESCON CUs.

You must define the CPs to both the hardware and the operating system as shown in the following sections.

If using the z/OS Storage Management Subsystem (SMS), be sure the Teradata devices are not included in an SMS Storage Group with other types of devices. Otherwise, the Automatic Class Selection (ACS) routines might change the specification of a Teradata device to some other type of device. It is imperative that an ACS routine never change the specification of a Teradata device.

Hardware Configuration Definition

Hardware Configuration Definition (HCD) is a program used to define the I/O configuration to both z/OS and the channel subsystem.

HCD is primarily an interactive tool and therefore uses a hierarchy of displays known as panels instead of the control statements of older methods.