unless you are on windows ....
You can also use an agent mounted on an nfs drive shared amongst servers - though I've only seen that described in the docs and I have my doubts.
Niall
Don't forget you have the mass-deployment agent whereby you can automatically "draw" a copy of the agent software from one central source, install and configure by simply running a single script on each target server. I recently did 25 Solaris boxes from scratch, in about 2 hours.
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-- Niall Litchfield Oracle DBA http://www.orawin.info