Nut and RAID on FreeBSD 7.0

[Kurt Buff]

On Jan 10, 2008 3:14 PM, Bob Johnson <fbsdlists at gmail.com> wrote:
> On 1/10/08, Derrick Ryalls <ryallsd at gmail.com> wrote:
>
> >
> > Perhaps I need to re-evaluate my line of thinking.  Light sometime
> > flicker, but power almost never goes out.  When it does it is either
> > back on in less than 1 minute, or out for hours.  If the UPS detects
> > critical correctly and gives me at least a minute before death, then
> > that should be plenty of time for the system to auto-shutdown.  Guess
> > I will have to do some experimentation tonight.
>
> While you experiment, keep in mind the following sequence of events:
>
> -- Power fails
> -- UPS signals low battery
> -- System shuts down
> -- Power returns before UPS shuts itself down
> --> System never reboots, because it never lost power.
>
> Getting around this is the tricky part. I haven't used NUT in about
> seven years, but back then the recommendation was to shut down to
> single user mode and run a script that delayed for some time longer
> than the remaining battery life of the UPS, then rebooted the system.
> There didn't seem to be an easy hook for running a script after
> shutting down to single user mode (maybe there is now).
>
> I haven't looked at NUT recently, but I expect the various flags that
> you are supposed to test are another way around this problem.

At which point, you either hit the power button manually, or you
telnet/ssh/web to your contollable PDU and tell it to remove power
from the outlet(s) for 10 seconds.

Kurt