Re: bbPress and BuddyPress forums
I don’t believe their is such a thing as “buddypress forums”, I believe buddypress requires bbpress for it’s forum capabilities.
WordPress MU will scale without question beyond the needs of any individual providing enough server backend power.
BBpress as a stand alone should be able to scale large enough for most people. Due to a the different nature of forum database structure, it isn’t as easy to breakup among many servers as a the mu blogs are. An active forum can easily have 100k’s of posts, and I’m not aware of a way to archive older posts into backup tables. BBpress uses 1 table for all posts, it would be possible (there might even already be a plugin to do this) to move each forum to a seperate table, and therefor possibly a separate server.
My concern would be for the XML-RPC mechanism used to talk to the forums. This was designed, with good caching, but on a very large buddypress install with 100’s of active groups and 10000’s of members I wonder how much overhead the xml-rpc adds compared to a straight database lookup. It does allow for the bbpress to be moved to a secondary server, which is good, and is safe as it stores a bbpress creditials and not database creditals if the admin account happened to get compromised. The nice part is, the it was written with the bbpress_live class, which could be replaced with any other class. So someone could, if so desired actually rewrite the class to talk to a vbulletin forum or other solution. It could even do direct database lookups and inserts if desired. I’m sure we will see this in the near future, as some large vbulletin sites may want to add the social abilities of buddypress, and maintain their forums, as buddypress groups.
I have only used BBpress inside of Buddypress, so I haven’t yet had to deal with scaling issues, as I beleive mine has about 45 posts total.