[redwards510]

We've been using Serilog/Seq and we're extremely happy with it. I'm a little surprised that you didn't mention the buzzword "Structured Logging", which is the special sauce that makes Serilog stand out. Instead of concatenating strings with values, you assign keywords to values which you can later search on. For example,

Log.Info("Customer# {customerNumber} completed transaction {transactionId}", customerNumber, transactionId);

Then using the Seq log viewer you can simply click on "transactionId" in the log line and filter by "transactionId = 456" or whatever. It's one of the most exciting advancements I've seen in the .Net logging world.

EDIT: I realized I didn't really answer OPs question regarding space. If you used Serilog, you can set up different sinks to export to, with different options. For example, you could send all your logs to mongodb, and just recent 1 week rolling logs to the Seq server.

[mdaniel]

When I've heard "structured logging" used, it has been in the context of much more key-value pairs than just having keywords next to values, e.g.

    Log.Info("customerNum={customerNumber} transactionId={transactionId} state=completed", cN, tID)

or the ever popular logstash-y format:

    Log.Info(LogState.Add("state", "completed").Add("customerId", customerId).Add("transactionId", transactionId));

where `LogState` would build up a key-value dict and its `ToString` would emit the logstash JSON format.

I guess the version that works best depends on the tool that is consuming the log text.

[rjbwork]

In the end, serilog, depending on the sink, makes your log look like the template, and attaches the meta data of your template variable names and replacement values to the message itself.