[Nut-upsdev] suspend to ram

Arjen de Korte nut+users at de-korte.org
Wed Aug 15 12:02:33 UTC 2007

> well i was really talking about suspend to ram, i do it on another pc with
> windows and it about tripples the battery runtime on that ups (it was at 5
> min and when the system suspended it jumped up to 74 min even then it
> would
> go to 73 then jump back to 74 min  i didnt really see it drop ) ,  as far
> as
> i know all the ups has to power in that state is the ram (about 10w~) on
> my
> script i run sync to hdds first to write any data to them then i suspend
> it
> to ram everything shuts off , hdds,fans (inc power supply fan), video
> card,..etc i think the only thing on is the ram and the led on the
> mainboard, i dont care about open programs being lost since its mosly used
> for a webserver , my only concern is lost data / curuption , can this
> happen
> in suspend to ram if i sync the disks first?

Let me get this straight. You're sacrify server uptime to maximize the
runtime of your UPS? Why? To be able to startup your server in maybe 10
seconds after a downtime of an hour or so? Most people would instead
prefer to keep it running until the battery lasts, cleanly shutdown the
system and then take two minutes to reboot again (maybe half that if you
suspended to disk).

> i was thinking about using upssched to suspend it about 12+ mins before
> battery runs out that way i would maybe get about 30-40+ minutes out of
> the
> battery, i have even heard you can unplug the pc while its suspended and
> it
> will run for awhile before powering off (i havent tried it though ), but i
> can undserstand that if the power didnt come back on it would be a bad
> shutdown

If that is a laptop, maybe, but don't try this on a server/desktop system.
If you pull the plug on that, it's over in a blink of an eye.

> i might take a look into suspend to disk but it seems more complicated to
> start up the system

If you already have suspend to RAM working, suspend to disk should be a
piece of cake.

Best regards, Arjen

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