LogFaces is created to be an out-of-the-box log server which can be easily hooked with existing applications using log4j as their logging framework. "Off the shelf" is the major feature - you simply install it next to your system and redirect your appenders to logFaces server; it works with TCP or UDP sockets - both well supported by log4xxx. It's up to you which processes, hosts or even classes should be working with logFaces- thanks to log4xxx configuration magic, all this is very simple and not intrusive.
Imagine that you are dealing with multi-host system which needs to be tested in QA. It could be a lot of data. LogFaces can partition this data for you and set you focused on particular aspect. For example, if you want to see only presentation tier related activities in correlation with what is going on in data layer. LogFaces viewer provides such capability; it's called log perspective. Perspectives allow you to focus on particular application on particular host or even packages and classes. And all this can be done without touching you production code.
LogFaces works with databases, we support Oracle, MySQL, PostgreSQL and Apache Derby. Data is collected, filtered and ready for different queries. Not only persisted, same data received from applications is also dispatched to clients. Routing is done in real-time and can be very fine tuned by each client separately. For instance, QA people can observe their system under test while integrators or developers can see what happened in theirs. All are separate, not colliding. Clients can be very remote; you can be in the office while looking how your system is doing on site.
LogFaces isn't necessarily for large systems. It can work with smaller applications too. If you don't need persistence and only need routing capabilities - no problem, database can be disabled. Some of our users having logFaces only for viewing log in real time.