HyperDB is an advanced database class that supports replication, failover, load balancing, and partitioning.
Nothing goes in the plugins directory.
Enter a configuration in
db-config.php in the directory that holds
wp-config.php. This may be the WordPress root or one level above. It may also be anywhere else the web server can see it; in this case, define
db.php to the
/wp-content/ directory. Simply placing this file activates it. To deactivate it, move it from that location or move the config file.
Any value of
WP_USE_MULTIPLE_DB will be ignored by HyperDB.