Previous section.

Universal Measurement Architecture Guide
Copyright © 1997 The Open Group

Distributed UMA

The performance management of distributed environments implies that in general data can be collected on separate network-connected hosts, archived on any host or hosts an administrator chooses to, and can be accessed by sufficiently authorised MAPs executing anywhere in the network.

Extensible UMA Services and Configurations

The UMA Data Services Layer is, for each host, the hub of UMA communications between hosts. In a simple form, this situation is depicted in Fundamental Distributed UMA Configurations & Communications .

Figure: Fundamental Distributed UMA Configurations & Communications

Fundamental Distributed UMA Configurations & Communications shows a full UMA configuration on the local host (the host executing a MAP) communicating with a remote host that is, in this case, executing only the bottom three UMA Layers.

It is quite possible on the other hand to have the local host exist only to be a platform for control and display of performance data collected elsewhere. In this case, it will not be executing a Measurement Control Layer nor a Data Capture Layer, but instead, just a Data Services Layer and the MAP (together with its linked MLI). Furthermore, its Data Services Layer is much simplified, since it has no local data collections to coordinate or process, and it may not even be supporting a local UMADS. This situation is depicted below in "Small" Data Services Layer on a Local Host .

Figure: "Small" Data Services Layer on a Local Host

Here the local Data Services Layer (referred to as "small") is much simplified, merely acting as a forwarding service for local MLI requests to the remote host and for responses and data from the remote host back to the MAP through the MLI.

In practice, one would like to deploy instances of UMA components that provide only those services that may be required in a given case. For example, there is no need to (nor is it desirable to) deploy an instance of the Data Services Layer that implements UMADS reading and writing on a host that is exclusively an object for data collection.

A related step to deploying only those UMA services required in a given instance is to deploy only those configuration components required. For example, there is no need to deploy either local Measurement Control or Data Capture Layers on a host that is used only for the analysis and display of performance data from other hosts.

Flexible UMA Services and Configurations depicts a sampling of possible UMA service and configuration instances.

Figure: Flexible UMA Services and Configurations

Moving from left to right, we first have a host that is used exclusively for analysis and display of data - it implements only the MLI and a "small" Data Services Layer. Next, is a "full" configuration that has all of the layers of the UMA reference model and all of its services - this host is used both as an object of data collection, a repository of archival performance data (UMADS), and as a platform for analysis and display applications. The next two platforms are used only for the collection of live data (they have no read or write access to UMADS) and so implement only "small" Data Services Layers. The rightmost platform additionally supports two local measurement applications, one that monitors its performance and issues local management commands (not part of UMA) that make adjustments to promote better performance of certain critical applications, the other to export some of the performance data via other protocols (to an SNMP-based monitor, for example).

Interoperability

The Measurement Layer Interface supports the semantics of distributed data sources and destinations. The effect of this is that a Measurement Application Program (MAP) can request data from a number of sources throughout the distributed systems and these will be presented, at the MLI, in a co-ordinated manner. In addition, a MAP can specify both the source and destination of the data, thus enabling it to control the storage of measurement data on a Performance Data Server. The Data Services Layer is responsible for co-ordinating the distribution of data, which it does by interactions between such layers on each system that is involved in providing a UMA service.

The default protocol and interface by which Data Services Layers communicate is TCP/IP with sockets (using the registered ports).

UMA messages contain information on byte ordering, enabling them to be used between systems which have different conventions.

Why not acquire a nicely bound hard copy?
Click here to return to the publication details or order a copy of this publication.

Contents Next section Index