This subsection discusses points to be taken into consideration when you determine the maximum number of measurement conditions for an IE probe and a probe that are defined in the Probe action condition settings file (esp.conf), and when you determine the measurement interval and timeout value that are defined in the measurement condition registration file (esptask.xml).
You must consider each parameters for both the IE probe and the probe.
PFM - Agent for Service Response can measure multiple Internet services concurrently. The number of measurement conditions that can be measured concurrently is specified as the maximum number of measurement conditions for an IE probe and a probe in the Probe action condition settings file (esp.conf). If the number of concurrent measurement conditions that is specified is greater than the set maximum number of measurement conditions for an IE probe and a probe, any excess measurement conditions will be processed sequentially.
In the example shown below, the maximum number of measurement conditions for an IE probe and a probe is 3, and the number of measurement conditions to be executed concurrently is 7. This example assumes that all measurement conditions terminate at the same time.
Figure 4-1 Example of measurement when the number of measurement conditions to be executed concurrently is greater than the maximum number of measurement conditions for an IE probe and a probe
The probes used to measure the services function as threads. The number of threads to be generated is the same as the maximum number of measurement conditions for the IE probe and the probes in the IE probe and the Probe action condition settings file. Therefore, when you determine the maximum number of measurement conditions for an IE probe and a probe, take into account the performance of the host where PFM - Agent for Service Response is run.
The purpose of the timeout value is to abort the monitoring so as not to affect the other IE scenario monitoring when the response performance of the IE scenario is extremely degraded. When a timeout occurs, PFM - Agent for Service Response treats it not as the degraded response performance of the IE scenario, but as the abnormal state. Specify the timeout value to each IE scenario.
The maximum processing time permitted for a single measurement is the timeout value that is set as a measurement condition. Set the timeout value to be smaller than the measurement interval, so that a single measurement is completed before the next measurement begins. If the value you specify as the timeout value is greater than the measurement interval, the timeout value will be reset so that it is the same as the measurement interval.
The target service's total response time depends on the status, such as the number of requests that arrive concurrently at the server providing the target service, and the status of the network connecting the server and PFM - Agent for Service Response. Specify for the timeout value a value that is greater than the minimum total response time when the service is running normally, so that a measurement is completed within the timeout value.
The following shows the recommended procedure for setting the timeout value for measuring by the IE probe:
Depending on the combination of the maximum number of measurement conditions for an IE probe and a probe, the timeout value, and the measurement interval, some measurements may not be completed within the measurement interval, thus disrupting the execution of measurements in a specific interval. To insure that measurement processing is completed for all measurement conditions within the specified measurement interval even if a timeout occurs, the number of measurement conditions, the maximum number of measurement conditions for an IE probe and a probe, the timeout value, and the measurement interval must all satisfy the following condition:
Following is an example in which this condition is not satisfied.
Figure 4-2 Example when measurement processing cannot be executed within the specified interval
This example measures eight measurement items (T1 through T8) in an environment in which the maximum number of measurement conditions for an IE probe or a probe is 3. Because the first T7 and T8 are not completed within the measurement interval, the measurement execution times for the second T2 and T3 are delayed, and this delay increases further at the end of the second T8. Thus, the delay in the measurement execution time accumulates to a point where performing the measurement at the specified interval becomes impossible. If this occurs, a warning message (KAVK08160-W or KAVK10100-W) is output to the log file. Check and, if necessary, revise the maximum number of measurement conditions for an IE probe or a probe, the measurement interval, and the timeout value.
PFM - Agent for Service Response uses the IE Probe Daemon and the Probe Daemon to measure a target's response time. The measurement result is output once to a report file. Agent Collector collects the most recent measurement result stored in the report file. Depending on the Agent Collector's collection interval settings and the IE Probe Daemon and the Probe Daemon's measurement interval settings, part of the performance data may not be stored. Therefore, you must take into account the following:
Figure 4-3 Example of collection schedule (1)
In this example, the third measurement result is not collected because the fourth measurement is completed before the result of IE Probe Daemon's third measurement or Probe Daemon's third measurement is collected by Agent Collector.
You can set Agent Collector's collection interval from PFM - Web Console. You use the measurement condition registration file to set the IE Probe Daemon's measurement interval or Probe Daemon's measurement interval. For details about setting Agent Collector's collection interval, see the chapter that describes agent monitoring in the Job Management Partner 1/Performance Management User's Guide. For details about the measurement condition registration file, see 7.3 Measurement condition registration file (esptask.xml).
Figure 4-4 Example of collection schedule (2)
In this example, the following shows the procedure for collecting data.
In this example, although the performance data of the IE Probe Daemon's or the Probe Daemon's third measurement is collected, the Agent Collector does not store the data so that the performance data from the second to the forth measurement (i.e. 12 minutes) lacks. Into this lack of the performance data, you can interpolate the data using the previously collected performance data.
For details about how to interpolate the data into the lack of the performance data, see 2.4.4 Interpolating performance data. Hitachi recommends that you properly specify the Agent Collector's collection interval and the IE Probe Daemon's or the Probe Daemon's measurement interval in order to prevent the lack of the performance data.
The following notes are on the service monitoring: