5.2.2 Notes about the functions of PFM - Agent for Service Response

(1) Considerations needed for performing successful measurement

This subsection discusses points to be taken into consideration when you determine the maximum number of measurement conditions for a probe and an IE 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 probe and the IE probe.

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(2) Notes about Agent Collector's collection interval settings

PFM - Agent for Service Response uses the Probe Daemon and the IE 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 Probe Daemon and the IE Probe Daemon's measurement interval settings, part of the performance data may not be stored. Therefore, you must take into account the following:

• Relationship between Agent Collector's collection interval and Probe Daemon's measurement interval and IE Probe Daemon's measurement interval:

  Specify the settings in such a way that Agent Collector's collection interval is equal to or greater than Probe Daemon's measurement interval and IE Probe Daemon's measurement interval. A guideline is to set Agent Collector's collection interval to twice the value of Probe Daemon's measurement interval and IE Probe Daemon's measurement interval.

• Relationship between Agent Collector's collection interval and Probe Daemon's timeout value and IE Probe Daemon's timeout value:

  Specify the settings in such a way that Agent Collector's collection interval is greater than Probe Daemon's timeout value or IE Probe Daemon's timeout value.

Example 1:

The following figure shows the Probe Daemon's measurement schedule or the IE Probe Daemon's measurement schedule and Agent Collector's collection schedule under these conditions: Agent Collector's collection interval is set to 360 seconds (6 minutes), the Probe Daemon's measurement interval or the IE Probe Daemon's measurement interval is 240 seconds (4 minutes), and the Probe Daemon's timeout value or the IE Probe Daemon's timeout value is 60 seconds (1 minute).

Figure 5‒3: 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 Probe Daemon's third measurement or IE 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 Probe Daemon's measurement interval or IE Probe Daemon's measurement interval. For details about setting Agent Collector's collection interval, see the chapter that describes agent monitoring in the JP1/Performance Management User's Guide. For details about the measurement condition registration file, see 8.3 Measurement condition registration file (esptask.xml).

Example 2:

The following figure shows the Probe Daemon's measurement schedule or IE Probe Daemon's measurement schedule and Agent Collector's collection schedule when Agent Collector's collection interval and the Probe Daemon's measurement interval or IE Probe Daemon's measurement interval are both set to 360 seconds (6 minutes), and when the Probe Daemon's timeout value or IE Probe Daemon's timeout value is 60 seconds (1 minute).

Figure 5‒4: Example of collection schedule (2)

In this example, the following shows the procedure for collecting data.

1. When the Agent Collector collects the Probe Daemon's or the IE Probe Daemon's measurement results for the first time, the Agent Collector does not collect the measurement result because the Probe Daemon or the IE Probe Daemon does not complete their measurement. The Agent Collector succeeds in collecting the measurement results for the second or later times.

2. Assume that the second collection of the Agent Collector is late due to the heavy burden on the machine or so. In this case, if the Agent Collector collects the measurement result after the Probe Daemon or the IE Probe Daemon completes their measurement, the Agent Collector collects their second measurement result.

3. When the Agent Collector collects the measurement result for the third time, the Probe Daemon's or the IE Probe Daemon's second measurement result is collected, but the Agent Collector does not store the measurement result because the collected result is already stored in the above procedure 2.

4. When the Agent Collector collects the measurement result for the fourth time, the Probe Daemon's or the IE Probe Daemon's third measurement result is collected.

In this example, although the performance data of the Probe Daemon's or the IE 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 3.4.4 Interpolating performance data. Hitachi recommends that you properly specify the Agent Collector's collection interval and the Probe Daemon's or the IE Probe Daemon's measurement interval in order to prevent the lack of the performance data.

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(3) Notes about service monitoring

The following notes are on the service monitoring:

1. If the port number for a probe and an IE probe defined in the measurement conditions for DHCP has already been used (such as when the machine on which this product is installed is running as a DHCP client), this product may not be able to monitor DHCP correctly.

2. PFM - Agent for Service Response ignores cookie information specified in the meta HTML tags that are acquired during monitoring of HTTP(S) and Web transactions.

3. With respect to an embedded resource acquisition error during Web transaction monitoring, this product continues measurement processing even if acquisition of embedded resources based on the default settings fails. To treat an embedded resource acquisition error as a monitoring error, specify the following settings in the Probe action condition definition file (esp.conf):

   Section name: WEBTRANS Probe

   Key name: skip_emb_rsc_error

   Value to be set: N

4. In Web transaction monitoring, the GET method is used to redirect the POST method.

5. In Web transaction monitoring, if response determination is to be performed on HTML whose character set is not Shift_JIS on Japanese OS or GB18030 on Chinese OS, specify the correct character set for the corresponding step.

   You use the <DEFAULT_CHARSET> or <CHARSET> tag in the Web transaction file to specify a character set.

   When the character set does not specified in the <DEFAULT_CHARSET> or <CHARSET> tag, Shift_JIS is assumed for Japanese OS, GB18030 is assumed for Chinese OS and US-ASCII is assumed for other OS.

   If the HTML character set cannot be specified with the <DEFAULT_CHARSET> or <CHARSET> tag, do not specify multi-byte characters in a character string used for response determination.

6. If FTP monitoring is to be performed in an environment in which a Windows firewall is in effect, reception of the FTP server's response message for logout (QUIT command entry) may fail. To avoid this, specify the following settings in the Probe action condition definition file (esp.conf):

   Section name: FTP Probe

   Key name: ignore_quit_resp_recv_error

   Value to be set: Y

7. In Web transaction monitoring, if a URL in a request to be issued contains the hash mark (#), PFM - Agent for Service Response treats the character string following the # as a fragment specification (with its location specified in HTML), and deletes the fragment part before issuing the request. Thus, if a defined URL or substitute string for a variable string contains a # character that is not intended to be the delimiter for a fragment, add a # character at the end of the defined URL.

8. In Web transaction monitoring, measurement may fail if the acquired HTML character set is not Shift_JIS on Japanese OS, and if the response determination information or substitute string for dynamic session management support contains multi-byte characters. Make sure that there are no multi-byte characters in the response determination information or in the substitute string for dynamic session management support.

   For Chinese OS, measurement may fail if the acquired HTML character set is not GB18030, and if the response determination information or substitute string for dynamic session management support contains Chinese characters.

9. Notes about searching elements that contain substitute strings in Web transaction monitoring:

   When a substitute string is obtained from HTML, elements containing the substitute string are searched for.

   In this case, the specifications of this product are as follows:

   (i) If an element with the specified name does not have the end tag (</element-name>), its start tag (<element-name>) up to the start tag of the next element with the same name is treated as the element. If there is no element with the same name, the start tag through the end of the HTML file is treated as the element.

   (ii) If the end tag of an element with the specified name (</element-name>) is preceded by the start tag of an element with the same name (<element-name>), up to the start tag of the element with the same name is treated as the element.

   (iii) If an element with the specified name is the null element (<element-name/>) and its attribute value is not enclosed in quotation marks (" or '), and if the attribute value is continued to the end of the null element (/>), the value up to / is treated as the attribute value.

   In the example below, the value of the value attribute is user01/:

   <input type=hidden name=userid value=user01/>

   To use user01 as the value of the value attribute, change the specification as follows:

   Suggestion 1: Change the null element to the start tag:

   <input type=hidden name=userid value=user01>

   Suggestion 2: Separate the attribute value and the end of the null element with a space:

   <input type=hidden name=userid value=user01 />

   Suggestion 3: Enclose the attribute value in quotation marks:

   <input type=hidden name=userid value="user01"/>

10. In Web transaction monitoring, if a substitute string contains a character that is treated as a delimiter in the URL, such as the ?, &, or =, PFM - Agent for Service Response replaces it with a variable string as is and issues the request. If you want to encode the characters treated as the delimiters in the URL string, specify the <SUBSTITUTE_FORCE_URLENCODE> tag in the Web transaction file. For details about the <SUBSTITUTE_FORCE_URLENCODE> tag, see 8.5.2 Format and definition of the Web transaction measurement conditions.

11. Measurement fails on a POP3 server that does not support POP3 UIDL commands. Some older versions of POP3 servers may not support UIDL commands.

12. In Web transaction monitoring, if a substitute string is to be searched for in the acquired HTML and the attribute value of some element specified in the HTML contains < or >, the substitute character search fails, resulting in an invalid measurement result.

13. In Web transaction monitoring, a transaction that uploads files using the POST method (to transfer files from this product to the monitored server) cannot be monitored successfully. Specifically, this applies when the following conditions overlap in the definition:

    • The POST method is used.

    • The message body is in the format multipart/form-data.

    • The message body contains a part (delimited by a separator) that specifies the filename attribute of the Content-Disposition header.

14. If the network connection between this product and the monitoring target goes through a proxy function, such as JP1/Cm2/Internet Gateway Server, the following items may not be monitored correctly:

    • DNS

    • DHCP

    • FTP

    • TCP

15. To use GB18030 as encoding type in Chinese OS, you cannot use the 4 bytes characters. If you use them, the measurement might not perform correctly.

16. When PFM - Agent for Service Response is started or reloaded, the definitions in the Web transaction file that are registered in the measurement condition registration file (esptask.xml) are verified. If the verification results indicate a syntax error^#, the Probe Daemon (a measurement process) cannot start. Correct the syntax error, and restart PFM - Agent for Service Response.

    #

    The following are examples of syntax errors:

    - An XML tag contains an error (a format error in the Web transaction file).

    - The user to be authenticated is specified, but no password is specified (including a situation where a password is not correctly registered with the esppasswd command).

17. If an OS to be monitored is Window Server 2012 or later and the failover function is used, the DHCP service cannot be measured.

18. The measurement of HTTP(S) and the Web transaction supports the following protocols in communication of SSL performed between a probe and the Web servers for the monitor.

    • TLSv1.0

    • TLSv1.1

    • TLSv1.2

    About SSLv2.0 and SSLv3.0 which are the protocol that is lower than the above, PFM - Agent for Service Response disables it. However, you can enable the enable_low_level_ssl_protocol key to general section of ESPCONF by setting when Web server aimed for monitor permits communication by these protocols. But we do not recommend that you enable SSLv2 and SSLv3 which are the protocol that is lower. For more information about enable_low_level_ssl_protocol key, refer to "Table 8-3 Definition in the General section".

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