Maybe you can use metal brackets set in concrete like is done during fence construction these days. That way the base of the wooden post is not sitting in concrete, where it will rot eventually.

Thanks, wonder what's the lifetime of a Pergola like? We are in Seattle area so pretty rainy here.

Well there is certainly plenty of them around in this area. (Where we actually don't get the hot and wet, rot inducing summers of the eastern US. And we don't get the same level of termite activity as in southern parts of the country). Surely how long each holds up would depend on how they are made and how they are maintained.

good point, we certainly want lower maintenance. Sounds like Vinyl pergola is a better option.