Oracle HTTP Server Metrics Oracle Application Server Tips by Burleson Consulting

Here we see three sections, system usage metrics, error metrics, and connection metrics.

OHS System Usage Metrics

The system usage metrics page shows CPU and RAM memory usage for the HTTP server.  Note that the RAM is displayed in a pie chart, with HTTP server RAM, Free RAM, and other.  On an active Application Server, there is normally little free RAM, as many components will expand to use the available RAM.

OHS Error Metrics

This shows the error rate as a percentage of total transactions, error rate since startup, and total errors since startup.  We also see a listing of all error types and a count of the type.  From this section we can click the Error Log and Logging Properties links for further details.

Clicking the Error Log link displays EM?s log page, with the HTTP_Server in the right-hand box. At the bottom of the page is a list of error logs from the HTTP_Server.  Select the error_log link to see the details (Figure 5).  To add logs from other components simply select the component in the left box and move it to the right box.  Em will add it?s logs to the available log list.

Figure 5: Enterprise Manager HTTP_Server Error_log Page

HTTP Server response and load metrics

Now we return to the HTTP server page (Figure 2 above) and click the Response and Load Metrics link. 

Figure 6: Enterprise Manager HTTP_Server Response and Load Metrics

This page provides a snapshot of the current load on OHS, including request throughput and processing time.  It also gives a snapshot of the number of active and idle processes on the server. 

Finding a performance problem in the application server is difficult, due to the number of components interacting within the server.  This is a good place to look for performance problems.  Slow response time and large numbers of active processes on OHS may indicate a need to add an additional instance to the cluster.  If one user appears to be experiencing a problem, you can drill down and get process information by selecting the Process Details link. 

Figure 7: Enterprise Manager HTTP_Server Process Detail Page

A processor that is gaining time may indicate a problem within the application server and assist you in tracking it down.

HTTP Server Module Metrics

Returning to the HTTP_Server page (Figure 2), we now select the Module Metrics link.

Figure 8: Enterprise Manager HTTP_Server Module Metrics Page

This page lists all modules that have had at least one request since OHS was started.  This can also be helpful in tracking down a performance issue.  Request processing time that is abnormally high could indicate a problem in the module or in a program called by the module.

HTTP Server Virtual Host Page

Returning to the HTTP_Server page (Figure 2), we want to look at the Virtual Host section.  Currently, OHS only has one virtual host defined and it supports SSL connections to the default server.  By selecting the Virtual Host?s Server Name we get the Virtual Host?s page.

Figure 9: Enterprise Manager HTTP_Server Virtual Host Page

This page provides a snapshot of the load and performance statistics for that virtual host.  There is also an Administration section that will allow you to update all the host parameters defined in the httpd.conf file for this virtual host. 

You can also create or delete a virtual host using Enterprise Manager.  Returning to the HTTP_Server page (Figure 2) we see that the Virtual Host section contains Create, Delete, and Create Like buttons.  At the far left of the Virtual Host section is a radio button that is on for our single virtual host.  That button is used with the Create Like button to create a new virtual host like the one selected.  Let?s create a new virtual host using the wizard.  Selecting the Create button starts the wizard.

Figure 10: HTTP_Server Virtual Host Creation Wizard Welcome Page

The Introduction lists the type of information you will need to successfully create the new virtual host.  This information was covered in the virtual host section of the httpd.conf file. Selecting the Next button takes us to the General page.

Figure 11: HTTP_Server Virtual Host Creation Wizard General Page

The General page allows you to set a DocumentRoot directive for the new virtual host.  It also allows you to select which type of virtual host you will create, IP, named, or default.  It defaults to the default type and the default DocumentRoot.  In this example, we are creating a name-based virtual host, which as we discussed earlier, allows hosts with different names to use the same IP address.  We left the defaults for the remaining items.  Selecting the Next button takes us to the Addresses page.

Figure 12: HTTP_Server Virtual Host Creation Wizard Addresses Page

Here we entered the DNS name for our new virtual host.  Since we are sharing the same IP as the default host, we did not enter a new IP address.  Selecting the Next button takes us to the Ports page.

Figure 13: HTTP_Server Virtual Host Creation Wizard Ports Page

For this example, we will just listen on the default port for the main server and continue to the Error Log page.  Notice that we skipped the Protocal page.  Since we are using the default server?s IP and ports we can?t change the protocol.

Figure 14: HTTP_Server Virtual Host Creation Wizard Error_log Page

Here we define a new error_log for our virtual host and leave the logging level at Warning.  The next page is the summary page.

Figure 15: HTTP_Server Virtual Host Creation Wizard Summary Page

This page lists all of our selections for the new virtual host.  Select Finish and Enterprise Manager updates the httpd.conf file and then restarts OHS.

Figure 16: HTTP_Server Virtual Host Creation Wizard Complete Page

Figure 17: HTTP_Server Restart Page

Once OHS has restarted, the new Virtual Host is now up and running.  You can see the additional code created by the Wizard in the httpd.conf file.

NameVirtualHost *
<VirtualHost *>
    ServerName vh1.localdomain.com
    ErrorLog /home/oracle/oraportal904/Apache/Apache/logs/vh1_error_log
</VirtualHost>

Very little additional code was needed since our new virtual host mainly used the default server?s settings.  When we return to the HTTP_Server page, our new virtual host is now listed.

Figure 18: Updated HTTP_Server Page

As we have seen in this chapter, the Oracle HTTP Server is the gateway between our clients and all other components of the application server.  By building OHS on the Apache web server, Oracle has created a proven, reliable, and secure communication interface with Oracle9iAS.  Later chapters will detail areas such as dynamic content and security, adding additional capabilities to the OHS and the application server.  The Oracle HTTP Server is not the base of Oracle9i Application Server but it definitely is the front end.

 

This is an excerpt from "Oracle 10g Application Server Administration Handbook" by Don Burleson and John Garmany.