Robert Frost said in “The Road Not Taken” : “Two roads diverged in a wood, and I,I took the one less traveled by, And that has made all the difference” For historical collection of data within the Tivoli Framework, the user has to decide for each table collected if it should be saved at the TEMA (Tivoli Enterprise Monitoring Agent) or TEMS (Tivoli Enterprise Monitoring Server). The default location is the TEMA, but we have found that users like to move this to the TEMS so that all of their data is located on one machine. This post deals with the pros and cons of saving historical data at the TEMA or TEMS. In other words, which road should you take?

Historical data is saved in a flat file in both locations and this flat file is called the short-term historical data file(STH). It is a binary file containing the last 24 hours of data that is named based on the *TABLE keyword in the dock{product code} file located on the TEMS. These files are named dock{product code}, where {product code} is the two-letter product code for the monitoring agent. For example, the Windows OS agent has a docknt file, 'nt' is the product code for the Windows OS agent. This docknt file shows that the NT_System warehouse database table is named WTSYSTEM for the short term history file. Here is a snippet of the docknt file:

*TABLE:    WTSYSTEM
*OBJECT:   NT_System
*CAPTION:  System

Thus, the *TABLE keyword defines the short term history file name(WTSYSTEM) and *OBJECT keyword defines the warehouse table name(NT_System) in the database. They are usually not the same as the short term history file name is shorter and less descriptive for use on all types of operating systems. This is confusing at times when the user tries to take the warehouse database table name and map it to the short term history file on the TEMA or TEMS. One way is to use the dock{product code} file. On Windows operating systems, the dock{product code} files are located in install_dir\cnps directory; on Linux and UNIX operating systems, the files are located in the install_dir/arch/cq/data directory. Or if you followed my previous blog entry on the WarehouseProjection spreadsheet, for each agent the spreadsheet defines the 'Attribute Group/TDW Tablename' for the warehouse table and 'Agent Tablename' for the short term history file name.

So, now that we have defined the short term history file(STH), which road should the user take? The road less traveled: TEMA or the road more traveled: TEMS

Saving short term history data at the TEMA.

Pros: Less data to be saved in the STH file. Less traffic over the network as the data only has to travel from the agent to the database. Data is not lost if the agent machine is off the network for any reason. If you are filtering the historical collection, collection at the TEMA also gives you more space for composing the filter.

Cons: Agent machines can be off the network and the STH file can grow in size. Historical data is not located at one location. Firewall circumvention may be needed.

Saving short term history data at the TEMS.

Pros: Data is in one location and can be monitored easier. There are firewall limitations in your network. You are not warehousing the data and only are interested in the short term 24 hour data that can be displayed using the Tivoli Enterprise Portal Server(TEPS).

Cons: More data across the network as the data has to go to the TEMS or remote TEMS prior to being sent to the warehouse database. More data is saved in the short term history file as all agents are saving data in one file. Performance of the TEMS is affected by the handling of the data and since more data is saved more processing has to occur. Because of this performance factor it is recommended that if you have to save at the TEMS to use a remote TEMS instead of the HUB TEMS. When an agent machine is off the network and the agent is still running, historical data is lost.

Conclusion

So, adding up all the Pros and Cons above, the answer is to best save the short term history file at the TEMA. Meaning “Two roads diverged in a wood, and I, I took the one less traveled by(TEMA), And that has made all the difference”

Tags:  tems warehouse tivoli-monitoring sth itm tema