portmaster -a on a live server

[Tom Worster]

though all i really need is mysql/apache/php i have about 100 ports
installed and portmaster -a takes a long time to complete (hour or two).

so i'm wondering if i ought to be concerned about new binaries being
installed over the old ones on the disk while the old images are loaded and
running as daemons.

instead of doing portmaster -a, is there any advantage to:

portmaster -a -x mysql\-server -x apache
portmaster mysql\-server apache
reboot 

in order to minimize the time that the old servers are running while the new
images are on the disk?

tom