Database Outages - Best Practices

I was asked to put together a proposal for regularly scheduled outages to perform database maintenance. At this time, my company does not have scheduled outages, and unplanned downtime is becoming almost impossible to plan or get approved.

If anyone has a "best practices" document that can be shared or referenced, that would be greatly appreciated. I have worked in several top fortune 500 companies, so we are looking to implement policies similar to those.

Keep in mind that my management actually doesn't buy the need for outages AT ALL. I will need to do a little selling here.

I would be curious to hear of other company's practices, as well as vignettes about what one must go through to prepare and implement an outage.

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