[Nut-upsuser] Shutdown the servers first, keep the network running

[Dan Langille]

On Sat, Nov 23, 2024, at 8:13 AM, Greg Troxel via Nut-upsuser wrote:
> Dan Langille via Nut-upsuser <nut-upsuser at alioth-lists.debian.net>
> writes:
>
>> I have an idea for my shutdown process at home. My goal: maximize the network run-time. At present, the UPS has a run-time of about 57 minutes.
>>
>> This is my idea:
>>
>> * shutdown the servers after 15 minutes of downtime (for me, that's when battery.runtime hits 40)
>> * leave the network gear (switches, firewall, wifi) running so I can continue with Internet access

....

> The other thing is that I more or less believe that running the UPS all
> the way out is probably rougher on batteries than shutting down when it
> claims 10m.  But I also believe that UPS service is really tough on
> batteries and they seem to be reliably in need of replacment at 4 years.
> And, almost every battery I have pulled from a UPS (which I do when it
> becomes troubled) has been messed up, usually a shorted cell or a very
> weak cell.  Whereas batteries proactively pulled after 5y from a FiOS
> ONT, are often ok.  So I am not at all sure that trying to be nice to
> the batteries is a good strategy.

I agree. I thought about that when I was writing my post. I'll aim to shut
down when there is about 10-15 minutes left.

> So I would recommend:
>
>   - shut down servers after 5 minutes of outage
>   - shut down firewall and killpower when runtime <10m (or maybe 5m)
>   - have some way to start servers, such as switch controllable by
>     firewall

I have an Eaton APU - which I first need to clean up and document what
is plugged in where.

>   - once you have a way to bring servers back hands off, consider server
>     shutdown at 30s of outage, and restore after 15m of no outage

30s is a bit short - but I take your meaning. I have spoken with my
electricity supplier and none of my outages were less than 30 minutes.

>   - going over all your non-server stuff and thinking if you can reduce
>     usage
>
>   - log outages and also transfer to battery events.  log remaining
>     runtime vs time so you can see what the mapping is from reported
>     runtime to actual runtime

I'm doing that via LibreNMS over SNMP in 5 minute increments. That might
be fine enough. That log remaining runtime will not get logged once the server
go down - that's what does the logging.

> Your outage patterns may be different, so I may be off about the precise
> timings.  I suspect though, that there is a gulf between "protection
> device restores power in seconds" and "truck roll".   28m for drive to
> fault, visually inspect, decide it's cleared, replace fuse, is amazing
> and only happens if the people are in the office next to the truck, and
> even then it needs more luck.

-- 
  Dan Langille
  dan at langille.org