The excessive request timeout health policy specifies an
acceptable percentage of requests that can time out after being routed
from the on demand router (ODR). The target timeout value can vary
depending on settings in your environment.
About the excessive request timeout health policy
The
excessive request timeout health policy defines an acceptable percentage
of timed out requests that are routed through the ODR. For each control
cycle of the health controller, the number of requests that time out
after being routed from the ODR is examined. If the percentage of
timed out requests exceeds the configured percentage, runtime tasks
are generated to correct the situation.
If
you enabled Intelligent Management for
your web server, the timeout value is determined using the read/write
timeout in the web server plug-in cluster properties (serverIOTimeout in
the plugin-cfg.xml file). The health policy calculates
the percentage of timeouts over a 60-second interval.
Default values
By default, the target timeout
value for requests is 60 seconds. The default value for the percentage
of requests that can time out in the excessive request timeout health
policy is 5%. However, setting other properties in your environment
can affect the target timeout value that is used.
Settings that affect the timeout value
The
following settings in the administrative console affect the target
timeout value:
- ODR outbound request timeout setting
To
change the setting, click and set the ODR
outbound request timeout value to a number of seconds.
- goodServiceTimeLimitSpec custom property
For
more information, read about autonomic request flow manager custom
properties.
- timeoutFactor custom property
For more information,
read about autonomic request flow manager custom properties.
- Average response time value that is defined in the service policy
To
change the setting, click . Specify Average response time as
the Goal type and enter a Goal value.
Determining the target timeout value
Depending
your configuration, the timeout value that is used as target value
for the excessive request timeout health policy can vary. The following
decision tree helps you determine the target timeout value for your
environment. The default setting is the path indicated with red arrows,
or a target timeout value of 60 seconds, which is the default setting
for the ODR outbound request timeout.
Figure 1. Target timeout value
decision tree.
The settings that affect the target
timeout value combine together to indicate the target timeout value.
- The value of the goodServiceTimeLimitSpec custom
property is used as the target timeout value if the goodServiceTimeLimitSpec custom
property is specified and is larger than the ODR outbound
request timeout value.
- The value of the ODR outbound request timeout setting
is used as the target timeout value if the goodServiceTimeLimitSpec custom
property is not specified, the timeoutFactor custom
property is not specified, and the ODR outbound request
timeout setting is set to less than 60 seconds.
- The default value of 60 seconds is used as the target timeout
value if the goodServiceTimeLimitSpec custom property
is not specified, the timeoutFactor custom property
is not specified, and the ODR outbound request timeout setting
is set to greater than 60 seconds.
- The timeout value is set to the product of the values of the timeoutFactor custom
property and the average response time of the service policy if the goodServiceTimeLimitSpec custom
property is not specified, the timeoutFactor custom
property is specified, and the goal type of the service policy is
set to average response time.
