How to redirect logs to a different partition

For logging on Windows :
Regedit
go to HKEY_LOCAL_MACHINE\SOFTWARE\CheckPoint\FW1\5.0
create FWLOGDIR and put the full path to the log you want to go to

For logging on Unix :
ln -s /path/to/new/logdir $FWDIR/log
If you're talking about Windows NT then there is a registry hack.

enter the HKEY_LOCAL_MACHINE\SOFTWARE\CheckPoint\FW1\4.1 path and add a new
string value form the edit-->new menu. name it FWLOGDIR.
add the directory name that you wsih to log to, and create the directory.
then bounce the firewall (fwstop/fwstart).