Constant ENV_API_MAX_CONNECTIONS 

pub const ENV_API_MAX_CONNECTIONS: &str = "RUSTFS_API_MAX_CONNECTIONS";

Maximum concurrently served connections on the main API listener.

0 (the default) means unlimited. When set, the accept loop stops accepting once the cap is reached and lets the kernel backlog absorb bursts, releasing capacity as connections close. This bounds file descriptor and memory usage under a connection flood.

The cap covers everything on the main listener — S3, admin, console, and internode gRPC — so size it well above peer-node count plus the expected client concurrency. Environment variable: RUSTFS_API_MAX_CONNECTIONS Example: RUSTFS_API_MAX_CONNECTIONS=10000