Tomcat Monitor

Applies to ReadyAPI 3.52, last modified on April 18, 2024

You use Tomcat monitors to check metrics of your Tomcat servers.


Add the following lines to the Tomcat startup script:

# You can add these lines anywhere in your startup script

For details on preparing Tomcat servers for testing, see Preparing Servers For Monitoring.

Monitor Settings

  • Port – The port used to communicate with the server.

  • User name – The user account ReadyAPI uses to connect to the server.

  • Password – The password used to connect to the server.

Frequently Used Metrics

The Tomcat monitor provides information about the load created by users on the application server. ReadyAPI displays the following statistics in charts by default:

  • VM Memory – Heap Memory Used – The current amount of memory used by a virtual machine. The large amount of used memory indicates heavy load or memory leaks.

  • VM Threading – Thread Count – The number of threads created on a virtual machine. Monitor this metric to get information about the number of created threads.

Here are some other frequently used metrics:

  • Thread Pool – Current Threads Busy – The percentage of busy threads on the server. Monitor these metrics to get the relative usage of the threads. This value should not exceed 80% in your soak and peak tests.

  • VM Garbage Collector – Collection Time – The garbage collector process has the highest priority in the system. If your machine spends a lot of time collecting garbage, it has fewer resources to work with incoming requests. Try to keep this value as low as possible.

Other Metrics

ReadyAPI Performance connects to Tomcat using JMX and exposes all available metrics. For a list of metrics created by the Tomcat community, see the Monitoring Tomcat page in the Tomcat documentation. Here is a list of metrics that ReadyAPI Performance can usually access:

Category Description Metrics
Cache Information about the cache on the server. One set of statistics per directory. Access Count
Cache Size
Hits Count
Data Source Information about Data Source usage. Num Active (%)
Max Active
Max Idle
Num Active
Num Idle
Request Processor Information about the CPU usage. One set of statistics per server instance. Error count (%)
Bytes Sent
Error Count
Max Time
Processing Time
Request Count
Session Information about sessions run on the machine. One set of statistics per directory. Rejected Sessions (%)
Active Sessions
Expired Sessions
Max Active
Rejected Sessions
Session Average Alive Time
Session Counter
Session Max Alive Time
Thread Pool Information about threads on the machine. One set of statistics per server instance Current Threads Busy (%)
Current Thread Count
Current Threads Busy
Max Threads
Operating System Information about the computer running JVM. Swap Space Total
Physical Memory Total
Virtual Memory Committed
Swap Space Free
System CPU Load
Physical Memory Free
VM Garbage Collector Information about the garbage collector. Collection Count
Collection Time
VM Memory Information about memory usage on the virtual machine. Heap Memory Used (%)
Heap Memory Committed
Heap Memory Max
Heap Memory Used
VM Threading Information about threads on the virtual machine. Total Started Thread Count
Daemon Thread Count
Peak Thread Count
Thread Count

See Also

Preparing Servers for Monitoring
Server Inspector
Load Testing Templates

Highlight search results