Jmeter log replay taking more time .. can we able to use access log sampler in multiple thread? if so how to share the log files to all the threads?
Please help.
You can convert your access log into a CSV file with a script and use CSV Data Set Config in conjunction with the HTTP Request samplers - this way you will get it replayed with the multiple threads. See Stop Making Assumptions! Learn How to Replay Your Production Traffic With JMeter article to get the idea in more details and see the example implementation.
However be aware that this way most likely you won't be able to replay complex end-to-end scenarios, only simple HTTP GET requests which are not authenticated can be replayed this way. For quick-and-dirty test plan it might be enough, however it is much better to come up with modular test plan, reusable components, full control of workload, etc. so I would rather recommend building a web test plan from scratch.
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When I run Jmeter from Windows CLI, after some random time, the tests are being stopped or stuck. I can click on ctrl+C (one time) just to refresh the run but part of the request will be lost during the time it was stuck.
Take a look at jmeter.log file, normally it should be possible to figure out what's wrong by looking at messages there. If you don't see any suspicious entries there - you can increase JMeter's logging verbosity by changing values in logj2.xml file or via -L command-line parameters.
Take a thread dump and see what exactly threads are doing when they're "stuck"
If you're using HTTP Request samplers be aware that JMeter will wait for the result forever and if the application fails to respond at all - your test will never end so you need to set reasonable timeouts.
Make sure to follow JMeter Best Practices
Take a look at resources consumption like CPU, RAM, etc. - if your machine is overloaded and cannot conduct the required load you will need to switch to distributed testing
There are several approaches to debugging a JMeter test which can be combined as a general systematic approach that I capable of diagnosing most problems.
The first thing that I would suggest is running the test within the JMeter GUI to visualize the test execution. For this you may want to add a View Results Tree listener which will provide you with real time results from each request generated:
Another way you can monitor your test execution in real time within the JMeter GUI is with the Log Viewer. If any exceptions are encountered during your test execution you will see detailed output in this window. This can be found under the Options menu:
Beyond this, JMeter records output files which are often very useful in debugging you load tests. Both the .log file and the .jtl file will provide a time stamped history of every action your test performs. From there you can likely track down the offending request or error if your test unexpectedly hangs:
If you do decide to move your test into the cloud using a service that hosts your test, you may be able to ascertain more information through that platform. Here is a comprehensive example on how to debug JMeter load tests that covers the above approaches as well as more advanced concepts. Using a cloud load test provider can provide your test will additional network and machine resources beyond what your local machine can, if the problem is related to a performance bottleneck.
I am using jmeter to load test a website. I have tested from 1 to 400 users. however while testing for above 500 users/threads, I am getting 401/unauthorized error for few users. Hope you'll help me to find out a solution to this problem.
I can think of 3 possible reasons:
There is a parameterization problem with your test, i.e. it sends wrong credentials, you can use i.e. Simple Data Writer configured to save requests and response data for failing requests and inspect it using View Results Tree listener.
JMeter gets overloaded and cannot properly perform correlation. In addition to point 1 check whether you're following JMeter Best Practices and ensure that JMeter has enough headroom to operate in terms of CPU, RAM, etc. using i.e. JMeter PerfMon Plugin
Your application gets overloaded and cannot handle 500+ users, check your application logs, resources usage, output of APM tools, etc.
When I have given 500 concurrent users load via jmeter my server throwing error message but the same time I have called same request via browser showing proper response. How it is possible? Is there any settings in jmeter for avoiding same.
It is hard to say what can go wrong without seeing your JMeter configuration, full server response, JMeter and application under test logs and network dump for browser and JMeter.
The whole idea of performance testing is mimicking real user as close as possible, so you need at least
Add HTTP Request Defaults and set JMeter to:
Download embedded resources
Use concurrent pool of 2-5 threads
Add HTTP Cookie Manager
Add HTTP Cache Manager
Add HTTP Header Manager
Correlate any dynamic parameters
Simulate any specific application behaviour (i.e. AJAX calls)
etc.
In addition to above recommendations: ideally given "good" JMeter you shouldn't see any "response messages", you should see a number of errors in final report so double check you:
Run JMeter in non-GUI mode
Storing only those metrics which are absolutely required
Follow other recommendations from 9 Easy Solutions for a JMeter Load Test “Out of Memory” Failure
beside, what Dmitri described above, I would also check the actual throughput the server returns in either cases.
Throughput depends a lot on the timers you configured in Jmeter to simulate think time.
Jmeter has no rendering and no javascript engine, so each thread is much much faster than a real browser.
I need to stress test a Server with around 3000 users conecting to it concurrently via SyncML Clients. For simulation of each user, a application needs to be launched which then connects to the server and does some operations.
Each user corresponds to each process.
The process is unix based and does http transactions based on SyncML Protocol.
I need to run the load for these 3000 processes for an hour or so.
Can you suggest best industry methods to fulfil such requirements?
Can JMeter or Locust help me in this?
Regards
You can definitely use Locust for this.
I wouldn't recommend starting processes to generate the load (even though it's possible), mainly because you won't get detailed statistics on what requests are made, how long they take to complete, etc.
Either you could just manually do the HTTP POST requests containing the SyncML data with the built in Locust HTTP client, or you could actually take something like pysyncml, and make your own SyncML client that reports the requests it does to Locust. It's fairly simple to do, you can read more about it, and see example, on the documentation page about custom clients.
Yes, JMeter can do this, though it's not clear to me what exactly the unix based processes needs to do.
JMeter can natively make HTTP POST requests and send XML data. Unless you have some very custom logic to make the requests, stick to JMeter on it's own.
If you must, you CAN execute a local process, but then you're severely limiting the number of users you can simulate per machine.
http://jmeter.apache.org/usermanual/component_reference.html#OS_Process_Sampler
For performance testing, I would like to capture some traffic from a production server and use that as a basis to replay the request to a test server in order to simulate a realistic load in our development environment. These are all stateless queries, so no issues regarding cookies, sessions, etc.
The Apache log timestamps everything down to a 1 second resolution, but that's not fine enough granularity for our peak times. What's the best way to capture more fine-grained timestamps for replay? And is there some ab-like load generating program that can use this data to replicate load?
Use jmeter.
https://serverfault.com/questions/84041/how-can-i-replay-apache-access-logs-back-at-my-servers-to-do-real-world-load-test
http://jmeter.apache.org/usermanual/component_reference.html#Access_Log_Sampler
As far as granularity with timestamps, you're not going to get better than that. However, you can randomize the time slots within jmeter. Even if your production traffic logs show hits every second, you can tell jmeter to speed that up drastically.
You could capture the network data of a production run, parse it, and then use that as a replay mechanism comparing the results of the production run and the test run (where desired). Oren Eini (Ayende Rahien) talks about something quite similar on his blog.
I know that there is (or was) a tool that allowed you to do load/performance testing based on recorded sessions, but I can't find it right now :(.
You can also use BadBoy to capture sessions to replay w/ JMeter:
http://www.badboysoftware.biz/docs/jmeter.htm