Question about table ownership

I'm setting up the first of many Informix production instances and I was wondering what thoughts anybody who's supporting existing instances would have on the following: Are there any drawbacks to having all tables owned by the informix user-id? How do you handle security? Is there anyway to grant a certain level of security to a group of users rather than issueing individual grants on each user-id? I'm not sure how performance is going to look so I'm setting up rootdbs, datadbs, logdbs and tempdbs dbspaces to start off with then I'll split out high activity tables and indexes as the need arises. Given this should I be trying to split off physical logs into their own dbspace? Any other dbspace thoughts. If I have multiple Informix instances running on the same unix box, we have an IBM SP2 running AIX 4.1.4, are there any special considerations? Any thoughts would be appreciated. Nigel Hall Safeway, CA, US