Re: DB effeciency with BP in conjunction with other blogs and BBPress installations
Here is a great introduction by Trent Adams to the HyperDB plugin.
As far as this issue is concerned:
If there are other blogs/sites created within the WPMU installation (but not BuddyPress) and other BBPress installations as well, is it recommended that everything reside in the same database, or should things like the additional BBPress installations use a separate database?
I don’t want to completely kill whatever server this could potentially end up running on, but quick response times and user integration between all platforms is key. The higher-ups estimate that there would be about 1,000 or so users for the duration of the event,
In this scenario, splitting WPMU data between multiple databases on the same database server will not give you much of an advantage. In fact, it could even slow read/write down slightly. But, if this is a temporary site, which it sounds like it might be, then splitting the load between multiple DB servers is probably not realistic.
The biggest issue will be how many web server and DB server cycles are dedicated to your domain and how many to other people’s domains. If you have a small hosting account, then you’ll absolutely need to upgrade to a decent VPS.