If I do not intend to use the coprocessors in my systems for some days, how do I shut them down to conserve the most power?
"micctrl --shutdown" sounds like the right thing to do. Indeed, it does something to make the coprocessors unavailable. However, consider the numbers:
1) With two coprocessors "online", the "micsmc" tool shows idle power consumption of the two coprocessors at ~200 W. When I go to the board Integrated BMC Web Console (IPMI) and view "Server Health" / "Power Statistics", it shows ~300 W. I presume this is the host plus two coprocessors, so the host is consuming 300 W – 200 W=100 W.
2) After "micctrl --shutdown", the two coprocessors go offline, "micsmc" gives a "lost card alert", and the power statistics in IPMI drops to 260 W.
Saving only 40 W by shutting down two coprocessors, does not sound like a real shutdown. They are still consuming ~80 W a piece in "shutdown" mode. Is there anything else that I can do to cut power during non-operation, except for pulling them out of the system?