This is intended for larger WordPress Network installs using an existing 1-3 character MD5 hash (by blog id) based multi-DB sharding structure. It supports 16, 256 or 4096 database shards. It also supports a separate database for blog id 1 and multiple VIP databases (home & VIP code contribution by Luke Poland).
It should support any plugin that works with (and accesses all data via) the regular WordPress database code.
It has been used to power MU version 2.7.1 through WordPress 4.8 sites and upgrade sites from 2.7.1 through to the WordPress 4.8.
A detailed installation guide can be purchased for a nominal fee.
This plugin is based on HyperDB which is the database plugin used by WordPress.com. Like HyperDB, this plugin autodetects whether a query is requesting a global or blog table.