What is NetLogger?

NetLogger is a methodology for troubleshooting and analyzing distributed application. The NetLogger Toolkit is a set of tools that help deploy this methodology. The methodology is described in more detail here .

Why is it called NetLogger?

NetLogger is short for "Networked Application Logger". NetLogger is NOT just about monitoring the Network.

What are the NetLogger Toolkit Components?

The Netlogger Toolkit includes a number of separate components. You may find one or more of these components useful for your end-to-end monitoring needs. See the NetLogger Manual for details on all these topics.
• NetLogger message format and data model: A simple, common message format for all monitoring events which includes high-precision timestamps
• NetLogger client API library: C/C++, Java, and Python calls that you add to your existing source code to generate monitoring events. The destination and logging level of NetLogger messages are all easily controlled using an environment variable.
• NetLogger visualization tool (nlv): a powerful, customizable X-Windows tool for viewing and analysis of event logs based on time correlated and/or object correlated events.
• NetLogger host/network monitoring tools: a collection of instrumented system monitoring tools: nl_vmstat, nl_netstat, an interface to Ganglia, etc.
• NetLogger storage and retrieval tools, including:
• netlogd: a daemon that collects NetLogger events from several places at a single, central host
• Archive: An event archive system for NetLogger data, based on mySQL
• nlforward: forward all netlogger files in a specified directory to a given location

What Language-bindings are supported for NetLogger Instrumentation library?

C, Java, and Python are fully supported, but only can easily construct a NetLogger event message using any language's string print function.

Is NetLogger Open Source?

Yes! It is under a BSD-style open source license.

What happened to the binary format, the activation service, and other features decribed in some of the NetLogger papers?

They were not used by anyone, and so they were removed to make NetLogger smaller and easier to install. If you really need the binary format for extreme performance, let us know and we can provide you with the code for this.

Is NetLogger compatible with Java's logging package (aka loj4j)?

Yes.

What is the overhead of adding NetLogger?

The overhead is very low. You can generate up to 5000 events/second using the C API, 500 events/second using the Java API, and 80 events/second using the python API which negligible impact on your application.

How do I view NetLogger log files?

Use the NetLogger Visualization program nlv, or you can also use gnuplot.

Other questions?

Let us know!