Hosting providers offering homeservers of any size can make use of MMR to lower costs associated with hosting media, and to manage/report usage of the media repository.
MMR can scale horizontally to cover thousands of servers on one logical media repo. See the "Deployment" section for more information on how to configure this setup.
A legacy architecture is to put a few hundred servers onto a single MMR instance, as MMR previously could not horizontally scale. A Redis layer was shared across all the MMR instances to supply a datacenter-wide cache without having to put thousands of servers onto that media repo. Documentation for this setup is available here.
Generally it is expected that hosting providers will use Docker as an installation method. CPU requirements are generally low (4-6 cores for about 500 hosts), however disk space and memory can be significant across all deployed instances.
To help keep individual processes working efficiently, it is recommended to deploy approximately 1 MMR instance per 500 possible hosts.
Disk space is strongly recommended to be managed with S3 or an S3-like service. Mounting a volume is possible, though usually datacenter deployments prefer to have zero ties to physical disks.