log4net vs. Nlog

Question

Anyone have experience for both? How do they stack up against each other?

We are planning on using one of them for logging in an enterprise application.

References:

log4net

nlog

EDIT: We have no existing dependencies to either nlog or log4net.

Answer 1

I was recently tasked to "prototype up some loggin'" for an upcoming project. I didn't have any logging framework experience. I researched, ran through tutorials, made toy apps, etc. on Log4Net, NLog, and Enterprise Library for a few days. Came back 3-4 weeks later and put them together into a cohesive demo. Hopefully some of this is useful to you.

My recommendation for our project is this:

1. Use a logging facade (e.g. Common.Logging, SimpleLoggingFacade) to avoid direct dependencies.
2. If we end up using Enterprise Library for other facilities, then use it for Logging, too.
3. If we end up using something with a dependency on Log4Net, use Log4Net.
4. If none of the above, use NLog. Which I'd prefer.

That's based on these findings (opinions!):

• All 3 frameworks are capable and can do some sophisticated things. We want a quality solution, but frankly don't need ultra high performance or 60 types of event sinks.
• All 3 have very similar basic concepts.
• Each has its own cool tricks, like really advanced routing, or dynamic log filenames, file truncating, etc.
• All 3 are pretty well documented in their own way.
• For a complete newb like me, they were all a little awkward initially. No drastic differences here for the basics. I got over it.
• When revisiting things a few weeks later, NLog was clearly the easiest to resume. I needed very little brush up on it. With Log4Net, I had to revisit a few online examples to get going. With EntLib, I gave up and did the tutorials all over again from scratch - I was totally lost.
• I couldn't figure out how to get EntLib to do some things like log to the database. It might be easy, but it was beyond my time limit.
• Log4Net and NLog have a small in-code footprint. EntLib is spammy, but I'd use a facade over it anyway.
• I accidentally mis-configured EntLib and it told me at run time. Log4Net didn't. I didn't have an accidental mis-config with NLog.
• EntLib comes with a nice looking app.config editor, which you 100% need. NLog has a config file schema so you get "intellisense". Log4Net comes with nada.

So obviously I like NLog so far. Not enough to use it in spite of having another solution available, though.

Answer 2

A key consideration that hasn't been much discussed is support and updates.

Log4Net hasn't been updated since version 1.2.10 was published April 19, 2006.

In contrast, NLog has been actively supported since 2006 will soon release NLog 2.0 supporting many platforms that didn't exist when log4net was last updated such as:

• NET Framework 2.0 SP1 and above, 3.5 & 4.0 (Client and Extended profiles)
• Silverlight 2.0, 3.0, 4.0
• .NET Compact Framework 2.0, 3.5
• Mono 2.x profile

Answer 3

Having had an experience with both frameworks recently, I thought I can share my views on each frameworks.

I was asked to evaluate the logging frameworks for an existing web application, I narrowed down my choices to NLog (v2.0) and log4net (v1.2.11) after going through various online forums. Here are my findings:

1. Setting/starting up with NLog is dead easy. You go through the Getting started tutorial on their website and you are done. You get a fair idea, how thing might be with nlog. Config file is so intuitive that anyone can understand the config. For example: if you want to set the internal logging on, you set the flag in Nlog config file's header node, which is where you would expect it to be. In log4net, you set different flags in web.config's appSettings section.

2. In log4net, internal logging doesnt output timestamp which is annoying. In Nlog, you get a nice log with timestamps. I found it very useful in my evaluations.

3. Filters in log4net - You better check my this question - log4net filter - how to write AND filter to ignore log messages and if you find an answer/solution for this, please let me know. I understand, there is a workaround for this question, as you can write your own custom filter. But something which is not easily available in log4net.

4. Performance - I logged around 3000 log messages to database using a stored procedure. I used simple for loop (int i=0; i<3000; i++... to log the same message 3000 times. For the writes: log4net AdoAppender took almost double the time than NLog.

5. Log4net doesnt support asynchronous appender.

It was sufficient comparison for me to choose NLog as the logging framework. :)

Answer 4

For anyone getting to this thread late, you may want to take a look back at the .Net Base Class Library (BCL). Many people missed the changes between .Net 1.1 and .Net 2.0 when the TraceSource class was introduced (circa 2005).

Using the TraceSource is analagous to other logging frameworks, with granular control of logging, configuration in app.config/web.config, and programmatic access - without the overhead of the enterprise application block.

• .Net BCL Team Blog: Intro to Tracing - Part I (Look at Part II a,b,c as well)

There are also a number of comparisons floating around: "log4net vs TraceSource"

Answer 5

For us, the key difference is in overall perf...

Have a look at Logger.IsDebugEnabled in NLog versus Log4Net, from our tests, NLog has less overhead and that's what we are after (low-latency stuff).

Cheers, Florian

Answer 6

First look at the rest of your stack.

If you are using NHibernate, it utilizes Log4Net directly. Other frameworks might have other specific loggers they need.

Other than that: both work fine.

I've settled on Log4Net myself. It can be a pain to configure, and if it isn't configured correctly it is a pain to figure out what went wrong. But you can make it do almost anything you would want from a logger.

If you don't have a standing issue with Log4Net, here is an article I wrote on how to get started with it: http://elegantcode.com/2007/12/07/getting-started-with-log4net/

Answer 7

Well .. I used Enterprise library for database logging tasks and now I switched to NLog due to performance bottleneck.

some comparison info :

http://pauliusraila.blogspot.com/2010/10/solving-database-logging-bottlenecks.html

Answer 8

I echo the above and do prefer nLog. Entlib is needlessly bloated.

Re:Log4net One thing that ALWAYS gets me with log4net is forgetting to add the following to the global.asax to init the component:

log4net.Config.XmlConfigurator.Configure();

Answer 9

If you go here you can find a comprehensive matrix that includes both the NLog and Log4Net libs as well as Enterprise Lib and other products.

Somebody could argue that the matrix is done in a way to underline the features of the only commercial lib present in the matrix. I think it's true but it was useful anyway to drive my choice versus NLog.

Regards

Answer 10

As I noticed, log4net locks their output files the whole time application is running, so you can't delete them. Otherwise they are similar.

So I prefer NLog.

Answer 11

Shameless plug for an open source project I run, but given the lively discussion about which .NET logging framework is more active I thought I'd post an obligatory link to Serilog.

To use within an application, Serilog is similar to (and draws heavily on) log4net. Unlike other .NET logging options, however, Serilog is about preserving the structure of log events for offline analysis. When you write:

Log.Information("The answer is {Answer}", 42);

Most logging libraries immediately render the message into a string. Serilog can do that too, but it preserves the { Answer: 42 } property so that later on, using one of a number of NoSQL data stores, you can properly query events based on the value of Answer.

We're close to a 1.0 and support all of the modern (.NET 4.5, Windows Store and Windows Phone 8) platforms.

Answer 12

I second NLog too because it works with unmanaged code too. I suppose it could be possibe to use log4net and log4cxx together, but NLog handles both managed and unmanaged code out of the box.

I also looked at Common.Logging, a facade that makes abstraction of the logging api, it supports log4net, NLog and Entreprise Library. I don't think i'll use it, but i like how they use lambdas to improve performance when logging is disabled (a feature shared with NLog and probably others).

Answer 13

You might also consider Microsoft Enterprise Library Logging Block. It comes with nice designer.

Answer 14

I think the general consensus is that nlog is a bit easier to configure and use. Both are quite capable, though.

Answer 15

Based on my experience, SmartInspect beats both NLog and log4net.

Its extremely easy to use, documentation is great, and you can view and filter previously logged messages with their interactive log viewer, which is a huge real world advantage.

One thing I like is the tabbed views of data, like the browser tabs in Chrome. Each tab can provide a different filtered view of the log.