Logging - GUI - Rolling - and Size

[sullimd]

I've been a Fortigate user, VAR, etc. for years.  Most of my customers have a small number of devices where logging may not be that important to them.  My larger customers look to me to diagnose issues, where I refer to the logs and CLI often.  However, I've never really paid much attention to the retention or size of the internal disk until recently.  A customer asked me about something that happened with a user a couple days ago, and I logged in and see that there's only ONE day of logs.

I have every rule logging ALL sessions.  Every web and application set to Monitor so i can log everything...  Yet there's ONE day of logs.  I've always thought it kept 7 days based on defaults, which most of my other customers do.

In the GUI, Disk Usage shows Free Space - 45GB.  Used Space 1.56GB.  Logs roll at midnight by default.

"#dia sys logdisk usage" shows:

Total HD Usage:  1784MB/60092MB

Total HD logging space:  45069MB

HD logging space used for vdom root:  1487MB/45069MB

My "max-log-file-size" was set to 20 by default.  Maximum-log-age was set to 7 by default.

So I got confused... Why is there a 45GB internal disk if I can't use more than ~1GB of it before it gets deleted in the GUI?  And why is there only ONE day when its set to 7?