Monitoring Server Performance

You must measure the system behavior before and after a change to check performance. You can monitor the performance of Proxy Server in different ways.

Monitoring the server does have some impact on computing resources. In general, using perfdump through the URI is the least expensive, followed by using stats-xml through a URI. Because using the Administration Server requires computing resources, using the Admin console is an expensive monitoring method.

For more information about the monitoring methods, see the following sections:

• About Statistics

• Monitoring Current Activity Using stats-xml

• Monitoring Current Activity Using perfdump

• Monitoring Current Activity Using the Java ES Monitoring Console

About Statistics

You can monitor performance statistics by using the Admin Console user interface, the stats-xml URI, and the perfdump. For these monitoring methods, the server uses the statistics it collects. None of these monitoring methods will work if statistics are not collected.

The statistics give you information at the configuration level, the server instance level, or the virtual server level. The statistics are broken up into functional areas.

For configuration, statistics are available in the following areas:

• Requests

• Errors

• Response Time

For the server instance, statistics are available in the following areas:

• Requests

• Errors

• Response Time

• General

• Java Virtual Machine (JVM^TM)

• Connection Queue

• Keep Alive

• Host DNS Cache

• Client DNS Cache

• In-Memory File Cache

• Thread Pools

• Session Threads, including profiling data (exists if profiling is enabled)

  Some statistics are set to zero if Quality of Service (QoS) is not enabled. For example, the count of open connections, the maximum open connections, the rate of bytes transmitted, and the maximum byte transmission rate is zero if disabled.

Enabling Statistics

To enable statistics, use Admin Console.

Collecting statistics causes a slight hit to performance.

To Enable Statistics (stats-xml) from the Admin Console

1. Select the Proxy Server instance.

2. Click the Server Status tab.

3. Click the Monitor Current Activity sub tab.

4. Choose Yes for Activate Statistics/Profiling?

5. Save and apply changes.

Monitoring Current Activity Using stats-xml

You can display statistics in XML format by using stats-xml. You can view the stats-xml output through a URI, that you need to enable, or you can view the stats-xml output through the CLI, that is enabled by default.

To Monitor Current Activity from the Admin Console

1. Select the Proxy Server instance.

2. Click the Server Status tab.

3. Click the Monitor Current Activity sub tab.

   Ensure that Statistics is enabled (see above).

4. Select the required Statistics from the dropdown list under Monitor Proxy Server Statistics and click Submit.

To Limit the stats-xml Statistics Displayed in the URI

You can modify the stats-xml URI to limit the data it provides.

1. Modify the stats-xml URI to limit the information by setting elements to 0 or 1.

   An element set to 0 is not displayed on the stats-xml output. For example:

   http://yourhost:port/stats-xml?thread=0&process=0

   This syntax limits the stats-xml output so that thread and process statistics are not included. By default all statistics are enabled (set to 1).

   Most of the statistics are available at the server level, but some are available at the process level.

   Use the following syntax elements to limit stats-xmlstatistics:

   • cache-bucket

   • connection-queue

   • connection-queue-bucket (process-level)

   • cpu-info

   • host-dns-bucket

   • client-dns-bucket

   • keepalive-bucket

   • process

   • profile

   • profile-bucket (process-level)

   • request-bucket

   • thread

   • thread-pool

   • thread-pool-bucket (process-level)

Monitoring Current Activity Using perfdump

To Enable and Use the perfdump SAF

1. Add the following object to your obj.conf file after the default object:

   <Object name="perf"> Service fn="service-dump" </Object>

2. Add the following line to the default object:

   NameTrans fn=assign-name from="/.perf" name="perf"

3. Restart your server software.

4. Go to http://computer_name:proxyport/.perf and access perfdump.

   You can specify the request time for the perfdump statistics. The browser automatically refreshes the statistics based on the time you specify. The following example sets the refresh time to every 5 seconds:

   http://computer_name:proxyport/.perf?refresh=5

Using Performance Buckets

Performance buckets enable you to define buckets and link them to various server functions. Every time one of these functions is invoked, the server collects statistical data and adds the data to the bucket. The cost of collecting this information is minimal, and the impact on the server performance is usually negligible. You can access this information by using perfdump. The following information is stored in a bucket:

• Name of the bucket. This name associates the bucket with a function.

• Description. A description of the functions with which the bucket is associated.

• Number of requests for this function. The total number of requests that caused this function to be called.

• Number of times the function was invoked. This number might not coincide with the number of requests for the function, because some functions might be executed more than once for a single request.

• Function latency or the dispatch time. The time taken by the server to invoke the function.

• Function time. The time spent in the function itself.

  default-bucket is predefined by the server. It records statistics for the functions not associated with any user-defined bucket.

Configuration

You must specify all configuration information for performance buckets in the obj.conf file. Only the default-bucket is automatically enabled.

You must enable performance statistics collection and perfdump.

The following examples show how to define new buckets in obj.conf:

Init fn="define-perf-bucket" name="acl-bucket" description="ACL bucket"

The above examples creates a bucket: acl-bucket. To associate this bucket with functions, add bucket=bucket-name to the obj.conf function for which to measure performance.

Example

PathCheck fn="check-acl" acl="default" bucket="acl-bucket"
...
Service method="(GET|HEAD|POST)" type="*~magnus-internal/*" 
fn="send-file" bucket="file-bucket"
...
<Object name="cgi">
ObjectType fn="force-type" type="magnus-internal/cgi"
Service fn="send-cgi" bucket="cgi-bucket"
</Object>

Performance Report

The Server statistics in buckets can be accessed by using perfdump. The performance buckets information is located in the last section of the report returned by perfdump.

The report contains the following information:

• Average, Total, and Percent columns show data for each requested statistic.

• Request Processing Time is the total time required by the server to process all requests received.

• Number of Requests is the total number of requests for the function.

• Number of Invocations is the total number of times that the function was invoked. This number differs from the number of requests because a function can be called multiple times while processing one request. The percentage column for this row is calculated in reference to the total number of invocations for all of the buckets.

• Latency is the time in seconds that Proxy Server takes to prepare for calling the function.

• Function Processing Time is the time in seconds that Proxy Server spends in the function. The percentage of Function Processing Time and Total Response Time is calculated with reference to the total Request Processing Time.

• Total Response Time is the sum in seconds of Function Processing Time and Latency.

The following example shows performance bucket information in perfdump:

Performance Counters:
------------------------------------------------
                           Average         Total      Percent

Total number of requests:               62647125
Request processing time:    0.0343  2147687.2500

default-bucket (Default bucket)
Number of Requests:                     62647125    (100.00%)
Number of Invocations:                3374170785    (100.00%)
Latency:                    0.0008    47998.2500    (  2.23%)
Function Processing Time:   0.0335  2099689.0000    ( 97.77%)
Total Response Time:        0.0343  2147687.2500    (100.00%)

Monitoring Current Activity Using the Java ES Monitoring Console

The statistics displayed through the Proxy Server Admin Console is also accessible through the Java ES Monitoring Console. Though the information is the same, it is presented in a different format by using Common Monitoring Data Model (CMM). You can also monitor your server by using the Java ES monitoring tools. For more information about using the Java ES monitoring tools, see Sun Java Enterprise System 5 Monitoring Guide at http://docs.sun.com/app/docs/doc/819-5081. Use the same settings to tune the server, irrespective of the monitoring method used.