Forum OpenACS Q&A: Re: connection to multiple server
No, it is not necessary that each database server you are connecting to have an openacs installation.
However, the three main pools should all be the same database and have the openacs tables installed. These pools are named main, log, and subquery.
You can create any number of database pools; so you could create another pool called remote1 for instance, and just run queries against that. Note, however, you would need to specifically use that pool (and thus that database) in your tcl code.