The C: drive on our SBS 2008 server just ran out of space. The culprit appears to be IIS, which is logging an incredible amount of activity in one particular log folder. Most of the IIS log folders look normal, but each of the daily files in C:\inetpub\logs\LogFiles\W3SVC1372222313 is at least 4.4MB, with the largest being yesterday's, at 1.67 GB!
The largest ones I can't even open on the server, but I've examined several of the smaller ones. They all show several dozen entries being made every few minutes that look like this:
2009-07-11 00:00:02 fe80::5558:434c:a610:405a%10 POST /ApiRemoting30/WebService.asmx - 8530 [DOMAINNAME]\[SERVERNAME$] fe80::5558:434c:a610:405a%10 Mozilla/4.0+(compatible;+MSIE+6.0;+MS+Web+Services+Client+Protocol+2.0.50727.4016) 200 0 0 3
Typically 40 or 50 of these entries will be made in the same second, with gaps of 2-5 minutes between each batch of entries. The other 1 percent of the entries in the file appear to involve WSUS.
I'm going to delete most of these files, because I don't really have a choice, but I'd like to know what's causing this out-of-control logging and how to put a lid on it in the future.
UPDATE: Okay, I've been able to examine a few more files. The bloat is apparently being caused by something going wrong when someone (i.e., me or another admin) logs in to WSUS interactively:
The trouble begins with a single log entry with no username (just "-"). It gets an HTTP status of 401.2 and a sc-win32-status code of 5.
This is followed by a long stretch of entries that alternate between no username and my own username. The ones with no username have an HTTP status of 401.1 and a sc-win32-status of 2148074254. The ones with my username are normal HTTP 200 entries.
So as far as I can tell what appears to be happening is that when I log in to administer WSUS via the SBS console, NTLM authentication is not persisting behind the scenes, causing continual reauthentication attempts throughout the session, transparently to me. Hundreds of these entries are being created every second, adding about 70MB per hour to the log file. I have no idea why this is happening.