Default Target Group and Fold/Unfold - Data Stream Architecture

Teradata Data Stream Architecture (DSA) User Guide

Product
Data Stream Architecture
Release Number
16.10
Published
August 2017
Language
English (United States)
Last Update
2018-04-17
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B035-3150
lifecycle
previous
Product Category
Software
Teradata Tools and Utilities

Beginning with DSA release 16.10, a default target group is created automatically on a DSU implementation that has ClientHandler installed on all the nodes. This default target group will expand and shrink when a database system unfolds or folds.

The name of the default target group is as follows:

defaultTargetTypeTGsystem_name

where TargetType is REMOTE_FILE_SYSTEM (disk file system - for DSA release 16.10, disk file system is the only target type)and system_name is the name of the system.

The following events trigger the creation of the default target group:

  • Configuring or reconfiguring a system
  • Adding a backup solution
  • Adding, deleting or restarting a media server

See the following examples of each scenario.

Default Target Group Example - Configuring or Reconfiguring a System

When a system is configured, a new system configuration is created to represent the nodes associated with the system. If all nodes have ClientHandler installed, a default target group is created. The number of devices allocated is based on the node level soft limit of the system load. See the following example:

System1 has 4 nodes. All nodes have ClientHandler installed.
  • node1 - Node softlimit 10
  • node2 - Node softlimit 20
  • node3 - Node softlimit 10
  • node4 - Node softlimit 20
The backup solution is defined for disk file system with two paths:
  • File system name: /path1/ Max number of open files: 100
  • File system name: /path2/ Max number of open files: 400

The default target group is created with the following configuration:

Target group name: defaultDFTGSystem1
Media Server File System Path Devices
ms1 /path1 2
  /path2 8
ms2 /path1 4
  /path2 16
ms3 /path1 2
  /path2 8
ms4 /path1 4
  /path2 16

ms1, ms2, ms3, ms4 are media servers on node1, node2, node3, and node4 respectively.

Default Target Group Example - Creating a Backup Solution

If a new backup solution is created based on the preceding system, a new default target group is created. See the following example:

System1 has 4 nodes. All nodes have ClientHandler installed.
  • node1 - Node softlimit 10
  • node2 - Node softlimit 20
  • node3 - Node softlimit 10
  • node4 - Node softlimit 20
The backup solution is defined for disk file system with three paths:
  • File system name: /path1/ Max number of open files: 100
  • File system name: /path2/ Max number of open files: 400
  • File system name: /path3/ Max number of open files: 500

The default target group is created with the following configuration:

Target group name: defaultDFTGSystem1
Media Server File System Path Devices
ms1 /path1 1
  /path2 4
  /path3 5
ms2 /path1 2
  /path2 8
  /path3 10
ms3 /path1 1
  /path2 4
  /path3 5
ms4 /path1 2
  /path2 8
  /path3 10

ms1, ms2, ms3, ms4 are media servers on node1, node2, node3, and node4 respectively.

Default Target Group Example - Adding, Deleting, or Restarting a Media Server

During unfolding, for example, from 4 to 8 nodes, 4 new nodes are added. Once all 8 nodes have ClientHandler installed, a default target group is created with all 8 media servers.

If a default target group already existed with 4 media servers, a new configuration is created with the new set of 8 media servers.

During folding, for example from 8 to 4 nodes, 4 nodes are removed from the system and the media servers on the nodes go offline. A new configuration (and default target group) is created with the available 4 media servers.

Restarting a media server behaves the same way as adding a new media server. A default target group is created after all the media servers are available.