this link may be useful;
www.oreilly.com/.../ch04_08.html

it discusses the samba logging
configuration. The setting worth a look is
called "max log size"
"The max log size option sets the maximum size, in kilobytes, of
the debugging log file that Samba keeps. When the log file
exceeds this size, the current log file is renamed to add an
.old extension (erasing any previous file with that name) and a
new debugging log file is started with the original name"

Ok. Now, about deleted those thousands of files.
Is there an easy way to do that?
He emailed and said he tried ctl-a but it doesnt select all of them and
then it hangs and he has to reboot.

I neglected the source
of my find.

Google "samba log level"
and you'll get results of O'rielly page,
and lots more which should be helpful.