Tonight, SQL Server decided to write a 14GB error log to disk - filling it up neatly, which of course had a couple of "side effects". Drat! All log file directories (HTTPERR, IIS, MailEnable, you name it) - everything except the SQL error log is on a separate partition for exactly one purpose: that no application log can stop the server dead in its tracks.
After clearing up the mess I thought "let's move the logs for SQL Server". Thanks to Alex I finally figured out where to do that - in the Configuration Manager:
Go to the Properties dialog, and modify the Startup Parameters (-eC):
Details can be found in the article Moving System Databases, section Moving the master and Resource Databases. Someone from Microsoft care to enlighten me as to why this log directoy has been hidden so far away from sight?