IBM Tivoli Monitoring: Implementation and Performance Optimization for Large Scale Environments

334 IBM Tivoli Monitoring: Implementation and Performance Optimization for Large Scale Environments

10.1.1 Hub monitoring server availability

The hub monitoring server is the heart of the monitoring environment. It has to be

treated differently than the remote monitoring server components. The hub

monitoring server contains the internal monitoring database, called the

Enterprise Information Base (EIB). The EIB contains the definitions of objects,

such as the information about managed systems, situations, policies and

definitions for historical data collection. It is the most critical component in the

whole environment.

Although policies used for automation runs on the hub monitoring server

independently, only a part of the situations run on the hub monitoring server.

Situations regarding EIB objects and correlated situations across multiple

managed systems run on the hub monitoring server. The situations on the

agents, if deployed, run independent of the hub monitoring server. If the hub

monitoring server fails, an agent cannot forward situation event notifications, but

the situation

actions will continue to run.

An agent can restart its own monitoring server via a restart action within the

situation running on the agent. The notification might be lost, however, because

the situations raised while the hub was down will be lost, unless they are still true

at the agent when they are restarted as part of the reconnection behavior.

The Warehouse Proxy agent and the Summarization and Pruning agent will work

independently, because the instructions are stored at the agent level.

Hub monitoring server monitoring

Basically, if you use a portal, you will see an error message box when the hub

monitoring server is not available, as shown in Figure 10-2 on page 335.

Important: A remote monitoring server also has an EIB, but with different

content. The hub EIB contains the

full content for the entire environment. The

remote monitoring server EIB only contain information for the agent that it

takes care of.

Also, the remote monitoring server EIB state (for example, situation status) is

more volatile, in that it is rebuilt every time the remote monitoring server

reconnects to a hub.

Tip: If the agent is reporting to a remote monitoring server, the agent can still

report situations to its remote monitoring server, even though the hub fails.

This data will later be lost when the remote monitoring server reconnects to

the hub and cleans its current situation status cache.