I'm just being testing a lot around for pagespeed. Doing this on a live system is a pain since you only can work between 2am to 7am. I do have employees creating content on the live system also comments are stored in the live db.
Wordpress seems to recommend to use one db (see: http://codex.wordpress.org/Running_a_Development_Copy_of_WordPress) Does this work with testing plugins and themes? Where do they store their settings? Kind of think this won't work since the plugins store their information in the database. Probably I need a local dev/staging installation or?
What are the best practices for staging wordpress?
Is there any smart way to only move the settings and updated files (theme, wordpress, ..) From dev to staging and from staging to live?
Is there any smart plugin allowing an staging environment? Because that would be off-topic.