Server Metrics Tutorial

Here at Load Impact, we’re constantly developing new features to help make our load testing tool even more powerful and easy to use. Our latest feature, Server Metrics, now makes it possible for you to measure performance metrics from your own servers and integrate these metrics with the graphs generated from your Load Impact test. This makes it much easier for you to correlate data from your servers with test result data, while helping you identify the reasons behind possible performance problems in your site. We do this by installing agents on your servers in order to grab server metrics data, which we can later insert into the results graph.

Having been a pure online SaaS testing tool, we don’t like the hassle that downloads and setups bring, so we’ve tried to make it really simple to set this up and use. (After all, we are trying to make testing more efficient, not more frustrating!)

Here’s 5 steps on how you can get Server Metrics up to a flying start:

Step 1 (Optional): Check out where Server Metrics appears in your Test Configuration

Go ahead and Log In to your account, then select the Test Configuration tab and create a new configuration. Alternatively, if you have current test configurations already set up, select one. Below the “User Scenarios” subsection, you should now find a section named “ Server Metrics”.  Click on “Go to Your account page”.
Alternatively, skip this step altogether and head straight to “Access Tokens” under the “Account” tab.

Step 2: Generating a Token

In order to identify our agents when they are talking to Load Impact, we need an identification key. We refer to this as a token. To generate a token, follow the instructions as stated.
(Yes, you only have to click on the “Generate a new token” button. Once :P)

Step 3: Download and install Server Metrics agent

Now comes the hardest part. You’ll need to download and install our Server Metrics agent for your server platform. Installation should be as basic as following the instructions in our Wizard, on in the README file.

Step 4: Run your test!

Once the server metrics agent is configured, you’ll immediately be able to select it in your Test Configuration (see Step 1). We recommend giving a name that describes the name of the server you’re installing it on for easier identification later on. From here, just configure and run your test as per normal.

Step 5: Viewing Server Metrics in your test results

Once your test has started, you should be able to see your Server Metrics results in real time, just as with all of our other result graphs. Simply select the the kind(s) of server metrics you wish to view in the “Add Graph” drop down menu. This will plot the results for the specific server metric that you wish to view.

And that’s it! You’re all set towards easier bottleneck identification 🙂
For an example of how these graphs are can help make your load testing life easier, take a look at the test results below. These results show your server’s CPU usage as load is being increased on your website.

Don’t think this is simple enough? Email support [at] loadimpact [dot] com to let us know how we can do one better!

Cloud Based Server-Side Load Testing

Just recently we announced the release of our Server Metrics agent. A feature that makes it possible to gather internal data from your server.

To get started with Server Metrics, please check out this tutorial that will guide you through the installation and setup process.

When Load Impact runs a test, the test server will collect a wide array of externally measured data. By measuring the load target from our end, we can quite easily pick up and store data about clients active, response time, transactions per second – just to name a few. We present this data to you in our web UI online, exported in CSV file or via our API for further analysis.

But there are a lot of other measurements that most of our users need to have to be able to do a better analysis of the performance and that is exactly what Load Impact Server Metrics tries to solve.

Fig 1. Memory and CPU usage of the target system

By installing the Server Metrics Agent on one or more target systems, our load testing server can pick up some internal measurements during the test and add those to the same data set. Load Impact  supports collecting data from several different target machines during a test, so it’s possible to get internal measurements from a fairly complex setup as well. The advantage of this is quite obvious.

Even if it would be possible to log this data separately on the target machines, you would end up with the task of trying to synchronize the time stamps of the internally generated data series with the data from Load Impact. Even if that’s of course possible to do, it’s going to be a bit of a hassle that you can easily avoid.

Technically, the Server Metric Agent software is a Python based script that will run as a service/daemon  on your target systems. It will require Python 2.6 and a fairly common library called psutil. Both Python 2.6 and psutil are open source and will run on pretty much every operating system we know of.  We offer installers for 32 and 64 bit Debian based Linux distributions, including Ubuntu, as well as for 64-bit Windows Server 2008 R2 and 2012.  For other systems, we offer the Python source code for download. Also note that in order to connect a Server Metric Agent installation to your, and only your, Load Impact account, you are required to generate a Server Metric token on your account settings page.