If you don't have a logfile yet, you first have to turn it on. Put
Code:
log on
fullserverinfo
into your autoexec.cfg or server.cfg.
You'll find the logfiles in the "logs" subfolder of "cstrike". But their output is buffered therefore initiate a mapchange before you try to open them...
Or if you have some terminal access to the server: watch the console
.