Multiple workers and nodes
Set $server->count to run multiple workers. More workers use separate processes; they do not share memory, subscriptions or open connections.
An external load balancer selects an application node. The application configures shared session/data storage. A WebSocket connection belongs to one worker until closed; cross-node broadcasting requires a broker or coordination layer such as Cluster with a matching Server version.
Check file descriptor limits, CPU/RSS, external connection pools and connection limits before increasing count. During shutdown, stop routing new connections, allow a bounded drain and support client reconnects.