b2evolution can handle multiple blogs, multiple site sections, multiple domains and multiple sites by default on a single installation. Thus it is generally unnecessary to install it multiple times on a single site/web hosting account or even a single server.
However in some extreme cases where you want to have multiple and clearly separated user databases for example, you might want to install multiple instances of b2evolution on the same web site or web server.
This is entirely possible. Just be careful about the following points:
- Install each instance in a different folder (of course)
- Use a different database for each. If this is not possible, make sure each one uses a different table prefix (see _basic_config.php).
- If you use a shared memory cache such as APC cache make sure each instance uses a different instance name (see _advanced.php). Otherwise you will have the sad surprise to see cached contents from one instance appear in the pages of another!