Time to wait before shutting down the TNAS = Until low battery

[TMzethar]

A quick search of this forum will reveal 50 topics devoted to UPS. Sorry, but I am not the only poster who has spoken to these issues and I don't see my function as curator of UPS issues.
For me one big issue (maybe, maybe not) is that @TM writes in the help sections to the effect that any devices (nas) using the TNAS UPS server function as clients must all be connected to the same UPS. NUT was never written that way; it was intended as a 'distributed network' servicing multiple server/client relationships. In this context it is likely (I don't know) @TM has implemented NUT i a non-standard manner. What I know is that it does not really work in (what I would say is) a logical manner relative to NUT manuals/tutorials. Nothing is really configurable since the internals of Linux itself have been "modified" as well as the configuration files of NUT itself and hidden behind obfuscating links and files.

We sincerely appreciate the time you have taken to offer your suggestion.
We regret to advise you that, due to a range of considerations, we are unable to adopt your proposal at present. Should circumstances allow, we may revisit this idea at a more suitable time in the future.

[Gremlin]

To what was your post in reference? Been a fair bit of water under the bridge since this was active (not that much has changed.

[rfbjr]

I will re-test my environment, I would have done it sooner but good or bad I have to crawl under the big table to yank the plug for the UPS out of the wall. I have all three devices (what is the plural for NAS) set to shutdown after 10min on battery.

Really should be two tests:
Pull plug, wait just 5 minutes and restore the power. See what happens, other than messages saying line power restored, nothing else should happen. Maybe that night's power off/on schedule might be affected?

Second test: Pull the plug and wait the 10 minutes and see what happens.

Update: IMO I see no purpose to keep working until the battery power is exhausted. If you are not there when this even happens, I would opt say the 10min delay to gracefully shut things down. If you are there and try to keep working (doing whatever), why generate more stress worrying about will I be able to finish whatever. If the rest of the place is in the dark but the devices can keep working, big deal.

I've been involved in two major power events, 9/11 while the building had diesel fuel to keep severs running, but the A/C was off. So you are tying to copy data before you ran out of fuel or the servers died via thermal. Tough choice.

2nd event was the office has UPS system battery only, for a room of 30 work stations. City had a blackout, the workers had time to save their work and leave.
(Glad I'm retired now)

[Gremlin]

I agree about the timing but maybe for a different reason. My APC units are configured so that a minimum battery level must be present before Start is allowed. If you hold the UPS on until battery is expended, it just takes that much longer for re-start while the batteries recharge from mains.
{My only "live" emergency was in Mississauga, Ontario when the flat roof of our single story office blew off overnight in a storm about 1990}

[Felix]

I will re-test my environment, I would have done it sooner but good or bad I have to crawl under the big table to yank the plug for the UPS out of the wall. I have all three devices (what is the plural for NAS) set to shutdown after 10min on battery.

Really should be two tests:
Pull plug, wait just 5 minutes and restore the power. See what happens, other than messages saying line power restored, nothing else should happen. Maybe that night's power off/on schedule might be affected?

Second test: Pull the plug and wait the 10 minutes and see what happens.

Update: IMO I see no purpose to keep working until the battery power is exhausted. If you are not there when this even happens, I would opt say the 10min delay to gracefully shut things down. If you are there and try to keep working (doing whatever), why generate more stress worrying about will I be able to finish whatever. If the rest of the place is in the dark but the devices can keep working, big deal.

I've been involved in two major power events, 9/11 while the building had diesel fuel to keep severs running, but the A/C was off. So you are tying to copy data before you ran out of fuel or the servers died via thermal. Tough choice.

2nd event was the office has UPS system battery only, for a room of 30 work stations. City had a blackout, the workers had time to save their work and leave.
(Glad I'm retired now)

Thank you for sharing your experience and detailed test scenarios.

Both of the scenarios you mentioned should work as expected:

* If the power is restored within the 10-minute delay period, the NAS will continue running normally. It will only record the power recovery event, and no shutdown will be triggered.
* If the UPS remains on battery power for more than 10 minutes, the NAS will execute the configured shutdown procedure to safely protect the system and data.

The 10-minute delay is designed exactly for this purpose — to avoid unnecessary shutdowns during short power interruptions while still allowing the NAS to perform a graceful shutdown during longer outages.

Thank you again for your valuable feedback and for sharing your real-world UPS experiences.

[Felix]

I agree about the timing but maybe for a different reason. My APC units are configured so that a minimum battery level must be present before Start is allowed. If you hold the UPS on until battery is expended, it just takes that much longer for re-start while the batteries recharge from mains.
{My only "live" emergency was in Mississauga, Ontario when the flat roof of our single story office blew off overnight in a storm about 1990}

Thank you for sharing your experience.

You make a very good point. Allowing the UPS battery to be completely exhausted can significantly delay the recovery process, because the UPS may need to recharge to a sufficient battery level before connected devices can restart.

Configuring the NAS to perform a graceful shutdown after a reasonable delay helps protect data integrity while also allowing the system to recover more quickly once stable power is restored.

Thank you for sharing your UPS configuration and your real-world experience. These insights are very helpful for understanding different power outage scenarios.

[rfbjr]

My first test with the three devices set to shutdown after 10min on battery worked. I pulled the plug on the UPS line power, all three alerted now on battery. One note, the switch for the NIC #1 connections was not on UPS, oops, but the switch for NIC #2 which is the network the devices transfer files and the UPS connections is on UPS. I plugged the line power back in after 5min, all devices indicated now on line power. Tonight I'll see if any scheduled shutdowns were affected.
Update: With the above test, the night's power schedule was not affected, each device powered down at the scheduled time and hours later all were powered back on via schedule as well.

Maybe today I'll do the same but leave the line power unplugged and see if all three do a graceful shutdown when the UPS runs out of battery power.
Checking first if any storms are predicted where I really might need the UPS.

[rfbjr]

Just completed 2nd test, disconnect line power and wait the 10min (what mine are set to).
UPS was showing 15 min after I pulled the plug, so good to know the 10 min is good enough.
All three devices sent a notification like the first test.
So yes after 10 minutes all three devices shutdown. But....
I thought it would generate an notification when the 10 minutes were up saying shutdown in progress. Yes I know "If power off" logic
I mean once the 10 minute timer when off, maybe the shutdown sequence could have generated something.
After for the webgui, no indication of anything happening. I had all three devices signed on.

I have no powered on any of the devices, please I hope there are no RAID resyncs.
EDIT: I'll wait 1/2 hr or so, let the UPS battery charge up some more before starting back up any devices.