Scheduled Maintenance Windows & Database Change Management

Hey Guys,  

We are a 24x7 shop (10.2.0.3 on Solaris 9) with several mission critical databases. Our main database supports our E-Business Suite (11.5.10.2) environment. We currently have monthly scheduled outages that typically last 6 hours. I manage the DBA/ERP team and we are under pressure to patch/implement more, but the business is REALLY pressuring us to have less and shorter scheduled outages. Obviously, this is a mutual exclusive situation, but logic doesn't always work...  

So, what I would like to know is for 24x7 shops, do you have regularly scheduled maintenance windows to apply patches, perform maintenance, etc...? If so, how long and how often are they? If not, do you have an environment that allows for rolling upgrades?  

My other question is related to versioning DDL object changes. Do you version control non-PL/SQL objects? If so, what tools do you use for table level change management? Do you use ITIL standards for table level change management?  

Thanks!  

Todd Carlson    

--
http://www.freelists.org/webpage/oracle-l