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The TREX server software comprises two parts:

  • TREX Instances

    These are the program files, configuration files, and so on.

  • Global TREX file system

    This is a directory structure, in which information about the TREX system instances is stored. For example, this information is required by management tools to start the TREX system.

    There is exactly one global TREX file system for a TREX system. When a TREX instance starts, it must have access to the global TREX file system. Otherwise, it cannot start.

When planning a distributed TREX system, you must decide which host the global TREX file system should be located on. This determines the installation steps that you work through later and which installation option you choose respectively. The following installation options are available:

Installation Option Description

Central TREX instance

Installing a combination of a TREX instance and a global TREX file system

TREX dialog instance

Install the TREX instance only

Global TREX file system

Installing the global TREX file system only

The global TREX file system can be located on any host, as long as all TREX instances have access to it when they start. It can be located on a host that belongs to the TREX system, but it does not have to be.

Note

SAP recommends the following for a distributed TREX system with centralized data storage:

Place the global TREX file system on the file server that the TREX data (indexes, queues, snapshots) is also stored on.

In order to serve as data storage, the file server and the connection between the TREX hosts and the file server must be highly available. If the global TREX file system is also located on the file server, you can be sure that the TREX instances can access it at all times.

For the installation process this means that you install the global TREX file system on the file server. You install a TREX dialog instance on every master, backup, and slave host.

SAP recommends the following for a distributed TREX system with decentralized data storage:

Place the global TREX file system on a host that is used as the master name server.

For the installation process this means that you install a central TREX instance on the host that is used as the master name server. On all other hosts, you install TREX dialog instances.

The graphic below depicts such a scenario.