A host is a computer where managed databases and other services reside. A host is one of many components or targets than can be monitored and managed by Oracle Enterprise Manager.
Monitoring refers to the process of gathering information and keeping track of activity, status, performance, and health of targets managed by Cloud Control on your host. A Management Agent deployed on the host in conjunction with plug-ins monitors every managed target on the host. Once hosts are discovered and promoted within Enterprise Manager, you can monitor these hosts.
Administration is the process of managing and maintaining the hosts on your system.
To view all the hosts monitored by Oracle Enterprise Manager, select Hosts on the Targets menu of the Enterprise Manager Cloud Control.
Note: Refer to the Oracle Enterprise Manager Cloud Control Administrator's Guide for information on discovering and promoting hosts, discovering unmanaged hosts, converting unmanaged hosts to managed hosts, and so on.
The host management capabilities in Enterprise Manager provide a quick glimpse of all the hosts on your system. This includes lifecycle status and configuration changes.
Using the host UI, you can:
Determine whether a particular host is available and whether there are incidents and problems associated with that host.
View statistics (metrics) applicable to each host. You have over 40 metrics to choose from! Examples of metrics include CPU, memory utilization, file sysmtem and network statistics. See the Oracle Enterprise Manager Framework, Host, and Services Metric Reference Manual for details about each of the host metrics.
Add and configure individual hosts.
Perform administrative operations on multiple hosts within the context of Enterprise Manager. This is possible by running the Host Command which enables you to type operating system commands against multiple hosts and immediately view the results.
Analyze job activity statistics including problem job executions, suspended job executions, and running jobs
Analyze compliance summary information to established standards. This enables you to determine what the issues are for the host and then correct the compliance violations as soon as possible.
To diagnose a host problem, consider performing the following steps:
Investigate the incidents and problems reported for the host.
Determine whether the statistics reported for CPU utilization, memory utilization, file system usage, and network utilization are within acceptable levels for different periods.
Ensure the host is compliant with the established compliance standard.
Investigate problematic job executions and why jobs are suspended.
Enterprise Manager allows you to view summary information about the targets on the host target. You can quickly determine how the individual targets are performing by analyzing the incidents and availability information. This gives you the opportunity to make changes as needed so the targets will function at peak performance.
Examples of targets that can reside on a host are: Database Instance, Web Cache, and Oracle HTTP Server.
When working with targets on a host:
Study incident information. The message associated with a particular incident provides a detailed description of what is wrong with the target.
Determine whether there are any compliance violations against this target.
If needed, remove multiple targets from the host.
This function is particularly useful when you want to eliminate, from the Management Repository and the Management Agent, those targets that no longer need to be monitored. This need can occur when a monitored target is deinstalled from the computer, or the Management Agent or host is no longer in service.
When removing multiple targets:
Ensure that the Management Agent is up when you are removing a target. If the Management Agent is down when the target is deleted, the target will be removed from the Management Repository only and not from the Management Agent. Therefore when the Management Agent is brought back up, the target will be back again.
Be aware that the Management Agent cannot be deleted unless it is the only target remaining on the host.
Tracking the storage resource allocation and usage is essential to large Information Technology departments. Unallocated and under utilized storage can be put to better use. Historical trends at a business entity level enable you to plan for future growth.
By default the storage history feature is not activated. Enabling storage history is expensive in regards to database resources. The amount of database resources used to calculate history data depends on the amount of storage data associated with the host target.