HP ProLiant DL580 G3 Server - Manual (Page 33)

Server component identification 33
This fan configuration allows the server to continue operating in non-redundant
mode if a single fan fails in either zone. If the system detects two fan failures in
the same zone, the server shuts down to avoid thermal damage.
Item Description Zone
1 Fan 1 1
2 Fan 2 1
3 Fan 3 1
4 Fan 4 1
5 Fan 5 2