[Beowulf] [EXTERNAL] Power Cycling Question

[Prentice Bisbal]

> On the "spool RAM to disk" idea - That's sort of like checkpointing, and it can take surprisingly long, so there's another tradeoff there.

Not really, especially not with NVMe disk drives. I have NVMe drives in 
both my laptop and my desktop, and it startling how fast they boot and 
resume from suspend with NVMe disks.

I think the bigger issue with this approach is if enterprise servers 
would support this. I believe there has to be some level of hardware 
support for this, which I doubt servers designed for constant-on use 
have. Someone please jump in and correct me if I'm wrong here.

Prentice

On 7/16/21 8:38 PM, Lux, Jim (US 7140) via Beowulf wrote:
> An interesting question.
> The power cycling reliability thing is probably not a big deal - the temperatures change a lot between light load and heavy load already, and if a "server class" PC can't take a power cycle per day, when the grungiest consumer unit can do it, I'd be surprised. It's not like you're cycling between -40C and 70C every hour like in an automotive application.
>
> Managing the chillers, though - That might be a bigger problem.
>
> And as Jörg points out, there's a fair amount of sophistication needed in setting your turn on and turn off thresholds.
>
> On the "spool RAM to disk" idea - That's sort of like checkpointing, and it can take surprisingly long, so there's another tradeoff there.
>
>
> On 7/16/21, 12:35 PM, "Beowulf on behalf of Douglas Eadline" <beowulf-bounces at beowulf.org on behalf of deadline at eadline.org> wrote:
>
>
>      Hi everyone:
>
>      Reducing power use has become an important topic. One
>      of the questions I always wondered about is
>      why more cluster do not turn off unused nodes. Slurm
>      has hooks to turn nodes off when not in use and
>      turn them on when resources are needed.
>
>      My understanding is that power cycling creates
>      temperature cycling, that then leads to premature node
>      failure. Makes sense and has anyone ever studied/tested
>      this ?
>
>      The only other reason I can think of is that the delay
>      in server boot time makes job starts slow or power
>      surge issues.
>
>      I'm curious about other ideas or experiences.
>
>      Thanks
>
>      --
>      Doug
>
>
>
>
>      --
>      Doug
>
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