Memory Events Test

For a ADC appliance to perform smoothly, the memory utilization of the ADC appliance should be optimal. Though high memory utilization may at times indicate that the appliance is running out of resources, it may also indicate other severe issues relating to memory. For example, when the same memory block is freed from a memory pool more than once, the the data in that memory block will be corrupted. If issues such as these are not detected at the earliest and rectified, data corruption may occur in most of the memory blocks leading to the performance degradation of the ADC appliance. To avoid such performance degradation due to memory related issues, administrators can use the Memory Events test.

This test proactively monitors the memory of the ADC appliance and reports the number of times bad memory was freed, the number of times duplicate memory was freed and the number of times memory was freed from a wrong memory pool. This way, administrators can figure out if there are impending issues with the memory and resolve it before serious data corruption leading to the downgrade of the ADC appliance occurs.

For this test to run and report metrics, the ADC appliance should be configured to create a Syslog file in a remote Syslog server, where the details of all interactions with the ADC appliance will be logged. To know how to configure a remote Syslog server for the use of the ADC appliance, refer to Creating a Syslog file in a remote Syslog server topic.

This test is disabled by default. To enable the test, follow the Agents -> Tests -> Enable/Disable menu sequence in the eG administrative interface, pick Citrix ADC VPX/MPX as the Component type, select Performance as the Test type, choose this test from the list of disabled tests list, and click on the < button.

Target of the test : A ADC VPX/MPX

Agent deploying the test : A remote agent

Outputs of the test : One set of results for the ADC appliance being monitored.

Configurable parameters for the test
Parameter	Description
Test Period	How often should the test be executed
Host	The IP address of the host for which the test is being configured.
Port	The port at which the host listens. By default, this is NULL.
Log File Path	This test reports metrics by parsing a Syslog file. Specify the full path to the Syslog file here.
Search String	By default, the Syslog file may contain information relating to a number of servers that are inter linked with the target ADC appliance. In order to obtain the metrics of the target ADC appliance alone, specify the hostname or the IP address of the target ADC appliance for which the logs are to be read from the syslog file, in the Search String text box. Using this search string the information in the Syslog file may be parsed and metrics may be collected.
Search String Index	Here, specify the cursor position after which the eG agent should search for the specified Search String (or the position up to which the eG agent should ignore while searching for the specified Search String) in the syslog file. For example, if the specified Search String appears in the syslog file at the 17^th position, then you may need to specify the Search String as 16.
DD Frequency	Refers to the frequency with which detailed diagnosis measures are to be generated for this test. The default is 1:1. This indicates that, by default, detailed measures will be generated every time this test runs, and also every time the test detects a problem. You can modify this frequency, if you so desire. Also, if you intend to disable the detailed diagnosis capability for this test, you can do so by specifying none against DD Frequency.
Detailed Diagnosis	To make diagnosis more efficient and accurate, the eG Enterprise embeds an optional detailed diagnostic capability. With this capability, the eG agents can be configured to run detailed, more elaborate tests as and when specific problems are detected. To enable the detailed diagnosis capability of this test for a particular server, choose the On option. To disable the capability, click on the Off option. The option to selectively enable/disable the detailed diagnosis capability will be available only if the following conditions are fulfilled: The eG manager license should allow the detailed diagnosis capability Both the normal and abnormal frequencies configured for the detailed diagnosis measures should not be 0.

Measurements made by the test
Measurement	Description	Measurement Unit	Interpretation
Bad memory freed events	Indicates the number of times bad memory was freed.	Number
Duplicate memory free events	Indicates the number of times duplicate memory was freed i.e., the number of times the same memory block was freed twice.	Number	When a memory is freed, the memory is returned to the memory pool from which it was allocated. This memory can be used by some other resources. If the same memory is freed again and in the meantime is allocated to another resource, then it indicates that the same memory is allocated to multiple uses and once the second memory free command is received, data in the memory block will be corrupted. A high value for this measure is therefore a cause of concern.
Memory freed from a wrong pool	Indicates the number of times memory was freed from a wrong pool.	Number	A high value for this measure is a cause of concern as this may indicate severe data corruption.