https://lenovopress.com/lp1049-thinksystem-sr630-server-xeon-sp-gen2#cooling

The SR630 server supports up to seven hot-swap system fans that provide N+1 cooling redundancy. SR630 server models with one processor include five system fans, and server models with two processors include seven system fans.
Configuration note: The SR630 FAN Option Kit (4F17A12350) includes two system fans that are required for field upgrades that add a second processor to the server. If two processors are selected in the initial server configurations, two fans for the second processor are derived by the configurator.