APC 60 kW SILCON UPS shutdown behaviour

[Anonymous user]

APC 60 kW SILCON UPS is loaded, so that it has autonomy about 2 hours on batteries. Servers are set to shutdown, while on battery after 30 minutes and it is NOT checked option 'Turn off the UPS after the shutdown finishes'. On UPS are set following settings:

- On Battery Shutdown Behaviour: Reboot On Line Return
- Low Battery Duration: 10 minutes

First question I have is what will happen in following situation: UPS runs on batteries about 40 minutes and then external power is returned. I think that servers will be shutdown after 30 minutes and after 40 minutes when external power is returned UPS will restart itself and servers will be booted up. Also, all the equipment which are on UPS and which are not possible to configure for gracefull shutdown will be rebooted. Is this correct ?*
In described situation setting on each server 'Turn off the UPS after the shutdown finishes' is not relevant, because it is not applicable to any SILCON UPS _(Is it correct?)_, so the servers cannot shutdown UPS no matter if this option is set or not. Is this correct ?*_

What will happen in described situation if the UPS is NOT SILCON and if on each server is checked option 'Turn off the UPS after the shutdown finishes'. I think that after 30 minutes running on batteries when UPS in one moment detect that last server is shutdown it will shutdown itself after time defined in 'Shutdown Delay' expires. In this way all other devices which are not servers will be shutdown as well. Is this correct? How UPS detects that all servers are shutdown? Does each server prior to shutdown send some informational packet about this to UPS?*

Another question that I have is what will happen if setting on server is set to shutdown after running on batteries after 1 hour and 55 minutes and UPS run into Low Battery regime after 1 hour and 50 minutes. When UPS run into Low Battery regime it should send signal to server to shutdown, but will server accept it or it would continue to run for another 5 minutes. I think that server should run another 5 minutes. Is this correct?

[TheNotoriousKMP_apc]

Hi Darko,

Hopefully I'm not overlapping answers from your other thread....I'll break it down by your questions...

1. +First question I have is what will happen in following situation: UPS runs on batteries about 40 minutes and then external power is returned. I think that servers will be shutdown after 30 minutes and after 40 minutes when external power is returned UPS will restart itself and servers will be booted up. Also, all the equipment which are on UPS and which are not possible to configure for gracefull shutdown will be rebooted. Is this correct ?+ Yes you are correct, anything that has not been powered down will reboot when the UPS cycles power to itself

2. In described situation setting on each server 'Turn off the UPS after the shutdown finishes' is not relevant, because it is not applicable to any SILCON UPS (Is it correct?), so the servers cannot shutdown UPS no matter if this option is set or not. **Is this correct ?**You are correct, you cannot turn off UPS after shutdown finishes when using PCNS and a Silcon

3. What will happen in described situation if the UPS is NOT SILCON and if on each server is checked option 'Turn off the UPS after the shutdown finishes'. I think that after 30 minutes running on batteries when UPS in one moment detect that last server is shutdown it will shutdown itself after time defined in 'Shutdown Delay' expires. In this way all other devices which are not servers will be shutdown as well. Is this correct? How UPS detects that all servers are shutdown? Does each server prior to shutdown send some informational packet about this to UPS?Just as the shutdown is completing, a packet is sent back to the NMC stating that "I'm off" (if the check box is checked for "Turn Off UPS after shutdown finishes") and that the UPS can begin its shutdown procedure, which includes Shutdown Delay. If it is not configured to shutdown, the UPS will then issue an immediate shutdown command in which, the PCNS clients must begin a shutdown immediately before they are dropped.

4. Another question that I have is what will happen if setting on server is set to shutdown after running on batteries after 1 hour and 55 minutes and UPS run into Low Battery regime after 1 hour and 50 minutes. When UPS run into Low Battery regime it should send signal to server to shutdown, but will server accept it or it would continue to run for another 5 minutes. I think that server should run another 5 minutes. Is this correct?When a "Low Battery" signal is sent to any PCNS device, it immediately begins a shutdown. It will not wait for a second message stating that the low battery state has cleared. The downside to this, is that you're assuming that when you started with 1h 55m of runtime that there was ZERO load fluctuation and 1h and 50m later, you have only 5m left. No server load is that static. So chances are after 1h 50m, your equipment will have already been powered down for at least 5-10 minutes.

[Anonymous user]

This means that in situation I described all equipment connected on UPS other than servers (routers, telco switch, ...) will suffer unecessary reboot ?

Is there a way to avoid this ?

[BillP]

since Notorious KMP and I arent three phase techs..

the only thing that i am not 100% sure on is the fact that if the power goes out, servers shut down, but then the power comes back on - the silcon wont reboot itself will it because it never turned off because it never lost power? unless of course the silcon is shutdown by one of the servers then it definitely will work (which I heard is best to avoid honestly..even though its an option when you dont have parallel silcons i thought) - any comments KP? do you agree?

[Anonymous user]

Hi,

This is what I think, as well.

If on all servers the option: 'Turn off the UPS after the shutdown finishes' is NOT checked, then no signal from server to UPS to shutdown will be sent. Therefore UPS will not shutdown till baterries are lost.

Question that I also posted on other thread is: what happens in situation if servers are shutdowned, UPS runs on batteries, and before UPS is shutdowned utility power is restored. Servers didnt send signal to UPS to shutdown. According, to what I see, UPS will NOT restart and servers will have to be started manually.

@Notorious K.M.P. what you mean by ' UPS cycles power to itself '

[TheNotoriousKMP_apc]

Darko,

The UPS cycling power to itself simply means that it has to change its state when power is returned to it. As described in the other thread, it does a "Self-Test" of sorts in that it transfers from battery to utility power, with a temporary transfer time, so that everything sees it as a momentary power loss, and either reboots, or powers back on. The UPS then goes back to an online state.

[TheNotoriousKMP_apc · Accepted solution]

Darko,

So I completely overshot my knowledge on this, assumed that this was the "state" change of the UPS when utility power returns.

Here's what the 3-phase techs told me.

UPS Goes on battery
PCNS shutsdown
UPS remains on battery
Utility power restored
UPS goes back online
PCNS clients remain down
No power interruption
Other equipment stays up, uninterrupted
PCNS clients need to be physically powered back on

The state change I was referring to is only when the UPS goes into Low Voltage Sleep Mode (After UPS is shutdown) and needs to power itself back up.

[Anonymous user]

Hi,

Thank you very much for your support and engagement !!! This concludes issues I asked on both threads.

Unfortunatelly, servers will have to be boot up manually in this situation ...

Maybe can be good idea for APC to start with plans for implementation of 'Wake On LAN'. It looks like simple and elegant solution for problem I described.

Greetings from Belgrade,

Darko