Web log analysis

[Richard Hector <richard@walnut.gen.nz>]

Hi all,

I need to get a handle on what my web servers are doing.

I remembered the name awstats, and installed it, but when I finally got 
it going (I had a typo in my nginx custom format), the output was 
somewhat opaque.

Things I'd like:

Ability to safely provide access to my customers
Ability to show trends over a decent length of time (at least a year)
Reasonable support for custom log formats, and ideally be helpful if I 
get it wrong ("It doesn't match" really wasn't very helpful)
Easy to navigate different views
Graphs would be nice
Not too much load on the web server
Free Software
Included in Debian preferred

Many of my sites are Wordpress sites, so I could choose from the many 
available plugins, but I suspect those will probably only start 
reporting from when they're installed; I have existing logs going back 
anything up to a few years. Generic is probably better.

Any suggestions?

Cheers,
Richard