Re:Server Hardware Super-Cycle 2022
by rbanffy on Tuesday January 18, 2022 @11:52AM
(#29981887)
> I'm sure the IBM Mainframe folks did it many decades ago
They could do that with CPU modules a couple generations back. I don't think the newer ones can do it though, at least not a CPU at a time. It's probably possible to power off a CPU drawer (4 CPUs on the Z15, IIRC) without too much hassle.
I remember seeing a colleague of mine doing it with memory and CPUs on a live Ultra Enterprise 4000, again, with memory and CPU. IIRC, he had to tell the OS the board was going to be pulled out before doing so and a light would signal it was safe to proceed. He was doing that because we used one machine to process a lot of logs overnight (in 1997).
Re:Server Hardware Super-Cycle 2022
by p_l on Tuesday January 18, 2022 @06:46PM
(#29987841)
CPU/memory live replacement in IBM mainframes is done on per-book basis IIRC. Used to be that single book had one or two CPU complexes (often each cpu was actually two running lockstep) but these days the density went way up.
They could do that with CPU modules a couple generations back. I don't think the newer ones can do it though, at least not a CPU at a time. It's probably possible to power off a CPU drawer (4 CPUs on the Z15, IIRC) without too much hassle.
I remember seeing a colleague of mine doing it with memory and CPUs on a live Ultra Enterprise 4000, again, with memory and CPU. IIRC, he had to tell the OS the board was going to be pulled out before doing so and a light would signal it was safe to proceed. He was doing that because we used one machine to process a lot of logs overnight (in 1997).