This is how I net out the requirements for large-scale (5k) relays from the capacity planning guide information and my own recommendations:
- 2-4 CPU cores
- 4-8GB RAM
- More storage (more varied sites, mailboxsites hosted)
- Increase _BESRelay_HTTPServer_MaxConnections to 10,240
- Adjust _Enterprise Server_ClientRegister_BatchCount/BatchDelay, for responsiveness needs
- Windows: Reduce TcpTimedWaitDelay to 30
- Linux: Increase nofiles ulimit to at least 16384