By Jonathan Klein on Jan 31, 2012
The enterprise manager agent has been entirely rewritten to meet the following goals:
plug-in life cycle support
first failure diagnostics built-in
scales to 10,000 targets
In this first blog of a blog series, we will focus on how Oracle Enterprise Manager 12c meets these goals. Subsequent blogs will go into further details about each of the areas above.
By and far the biggest change is the plug-in model. Plug-ins offer the following advantages over the previous target modeling supported by the agent:
independent life cycle from the agent
can be installed/updated without bouncing the agent
simple registration of user supplied libraries as needed
scheduled based or on-demand discovery of targets
A plug-in consists of two pieces; the discovery component and the monitoring the component. Plug-in upgrades currently require the agent to be restarted for the new plug-in version to take affect although the install of the new plug-in can be performed while the agent is still running. There is one exception to this – the first time a plug-in is deployed and installed the agent is not required to be stopped.
The discovery component of the plug-in works with the new discovery framework .Discovery can now be performed by on-demand and scheduled with the typical schedule occurring daily. As the discovery process finds additional targets to monitor, the administrator is prompted if they wish to monitor those targets. Once the decision is made, the management server ensures that the agent has the proper monitoring plug-in and then proceeds to add those targets to the agent.
The monitor component of the plug-in contains the metric definitions, the non-static properties, the default collection schedule and any additional scripts/libraries required by the plug-in to monitor. Also new in 12c are metric extensions which allows user/administrators to add additional metrics to a target with user supplied scripts.
Diagnosis of issues is always a difficult process, but the new agent, being written from the ground up has put in a significant amount of diagnostic tools. Even in the face of all that additional processing, the new code base consumes less CPU on average than the previous versions and is capable of scaling to large number of targets. To date, we've successfully measured target counts of approximately 5000 targets being monitored with near linear scaling. We therefore believe that 10,000 targets is realistic.
Below is a graph comparing the average CPU consumption of the 12c version of the agent (in green) against the 11g version (in red) for database targets.
The rewrite of the agent also includes an improved EM agent home page as well as a much enhanced agent side metric browser. There are numerous enhancements to enable the agent to continue functioning in the face of 'failures', such as three strikes suspension based policies for collections, as well as more control services available to the administrator.
My next next blog will focus on some of the diagnostic tools that are available for both administrators and Oracle personnel.
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