eTester JavaAgent errors "Agent communication lost" - "e-Test agent stopped

680571

Has anyone seen in eTester 8.20.555.00 the problem of too many JavaAgent processes resulting in "e-TEST agent stopped responding" or "Agent communication lost" errors? Is there an upper bound to how many eTester JavaAgent transactions that can concurrently run?

645110

Hi,
To reduce the likelihood of the agent crashing try doing the following:
* In eLoad, for each of the scripts, change the property named "Maximum users per process" to 100.
* In eLoad, for each of the scripts, change all 3 properties in the "VU Display" section to Never. The 3 properties in the VU Display section are "View all responses" , "Show Request Headers", "Show Response Headers".
* In eLoad > Tools > Options > Reporting" change the field named "Reporting Data Collection Interval" to a number between 30 to 60. It seams like a high number, but you will notice that the data is not lost, the agent averages out the numbers before sending them to the eLoad controller.
* Optional: For better stability try using an agent computer for every 1000 virtual users. Note that the number "1000 virtual users" is arbitrary based on experience. There are normal desktop computers that can run 3000 virtual users with no problems. It depends on the computer specs, ramp up, number of scripts, different instances of user defined profiles, number of navigations per page, and some more variables.

Running "too few" users per processes makes eload to create more processes, high number of processes in an operating system starves the computer CPU which can result in the agent or eLoad instability. Too few users per processes is a subjective number that depends on the specs of the computer and the total number of virtual users that will be in the load test . Generally speaking, having 100 users would be fine for many systems, having less than 10 users per process can slowdown a computer with only 100 to 200 virtual users.

It is difficult to estimate the upper bound to how many JavaAgent transactions can concurrently run in a computer because there are many variables. Some of the variables are: the computer specs, the quantity of http navigations in a script, and the total number of virtual users running. I can tell that you can try running with less than 10 scripts per eLoad installation (and if still with problems reduce from 10 to 8). Therefore if you have 15 scripts that will run concurrently, try having 2 computers each with an eLoad installation and put lets say 8 running in one and the rest in the other.

I hope it helps,
Zuriel