[Nut-upsuser] Synthesize low batt (LB) fron SNMP UPS which doesnot support this?

[gene heskett]

On 5/16/23 14:09, Carsten Aulbert wrote:
> Hi Roger,
> 
> On 5/16/23 17:00, Roger Price wrote:
>> Hello Carsten, That's what I did but for a much simpler setup. I live 
>> in an area with a lot of lightning, and my shutdown criteria is to be 
>> able to shut down repeatedly during an electrical storm.  The NOTIFY 
>> and CMDSCRIPT and the upssched-cmd logic are written up in detail in 
>> chapter 7 of https://rogerprice.org/NUT/ConfigExamples.A5.pdf .
>>
>> Chapter 8 contains a detailed description of a hypothetical 
>> installation fed by multiple UPSs.
> 
> wow, that looks like a LOT of content to digest but I'm not so sure if 
> our problems align that well (but then I only briefly skimmed over it).
> 
> Luckily for us, our power grid is really stable, I think we only had 4 
> or 5 outages lasting more than a fraction of a second over the past ~ 15 
> years. Thus, we use our UPSes mainly for providing clean and stable 
> power to our computing center with the bonus of have power when the 
> mains go down.
> 
> We shut down the compute nodes via upssched and a 30s timer. If the 
> power cut is shorter than that, they will simply continue running as the 
> timer is cancelled by nut. Otherwise they will simply power down and 
> stretch our 6-8 minutes battery buffer to much longer.
> 
> What I'm more worried about then are the storage servers, networking, 
> head nodes and a couple of special nodes which are powered by both UPSes.
> 
> We could use upssched also for those nodes, but the pipelining of 
> messages makes it a bit hard to have a final "stateful" service working 
> around the missing LB flag. This would need to actively query the UPS 
> and act after battery.runtime or battery.charge is too low overall. My 
> simple approach there did not work (effectively looping in the script) 
> as the next message from upssched would simply wait in the pipeline 
> while my script was still looping.
> 
> We could also use upsmon to call our script instead of upssched which 
> then would need to handle being called multiple times and coordinate 
> what to do based on the messages being passed.
> 
> Both cases would probably need our own running service which would need 
> to be fed messages and then act based on their own UPS queries. Probably 
> doable, but not that nice.
> 
> Idly browsing the client sources, I guess I could try to add our logic 
> here[1] and use [2] to gather the battery stats from our UPS and then 
> decide if this UPS is considered critical or not. But for this, I would 
> need to dust off/excavate my ancient poor C knowledge ;-).
> 
> I guess I will give this a try unless someone has a brilliant idea and 
> could save my sanity.
> 
> Cheers
> 
> Carsten
> 

Take an extra vitamin b1 and start hacking ;o)

Seriously, if its that important, do as I did when my last wife was 
dying of COPD.  Leave your ups setup as is but for under $10k (USD), 
have an automatic home sized standby generator installed to run the 
important stuff, then your power outages won't last more than startup 
lags, 5 or 8 seconds.  Because we have central air, I bought the biggest 
generac, 20kw, nat gas powered version about 13 years back, but generac 
hasn't answered the phone in 3 or 4 years, & the controller died a few 
months back so the label got changed from generac to kohler, same 20kw 
rating.  So I have more than $10k usd in it now, but you should be able 
to src a smaller one if the AC is not in the picture for quite a bit 
less.  I've had several multiday outages here, plus the 15 minute weekly 
test so the generac still has the synth oil I put in it to assure cold 
weather starting, and 157 hours on its clock.  Its currently sitting in 
the back yard, needing a controller or this one fixed, if you are local 
to northern WV, USA, $5k and a hoist will put it in your pickup. You'll 
need a transfer switch too.

> [1] 
> https://github.com/networkupstools/nut/blob/e3bdc28476700c7396bdde912e5789ccb7ecb1d7/clients/upsmon.c#L925
> 
> [2] 
> https://github.com/networkupstools/nut/blob/e3bdc28476700c7396bdde912e5789ccb7ecb1d7/clients/upsclient.h#LL105C1-L107C33
> 
> 
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Cheers, Gene Heskett.
-- 
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