Server startup after power returns to UPS

[Anonymous user]

We have a Smart-UPS 1500 RM with the network management card and two Apple Xserves connected to it.

The Xserves are running the PCNS software.

The runtime is about 40 minutes, and PCNS on the Xserves shuts the servers down after the "On-Battery" condition has lasted for 15 minutes.

After the Xserves have shut down, the UPS continues on battery power until the battery is drained. PCNS is not configured to shut down the UPS after the Xserve is shut down.

The Xserves are configured to restart after a power failure.

My problem is that when power is restored to the UPS after the Xserves have shut down, but while the UPS is still on battery power, the Xserves do not boot up again. Question 1: What can I do to ensure that the Xserves start up when power is restored to a UPS on battery power?

I'm not sure what happens if power is restored to the UPS after the battery has been drained and the UPS has turned itself off, as I haven't tested that yet. Question 2: Should the Xserves start up when power is restored to a UPS that has turned itself off?

I've read these two threads, but I'm not sure if the information applies to our setup:

https://community.se.com/t5/APC-UPS-Data-Center-Enterprise/bd-p/datacenter-forum

https://community.se.com/t5/EcoStruxure-IT-forum/bd-p/ecostruxure-it-forum

Thanks for any help.

Audun

[Anonymous user]

{quote:title=The Notorious K.M.P. wrote:}{quote}\r\n> Answer 2: If the UPS is off, power is cutoff, therefore the XServe cannot power itself up.\r\n\r\nAnd it won't power up again when power is returned to the UPS after it has turned itself off because the battery has been drained?

[TheNotoriousKMP_apc]

audunr wrote:Question 1: What can I do to ensure that the Xserves start up when power is restored to a UPS on battery power?

Question 2: Should the Xserves start up when power is restored to a UPS that has turned itself off?>

Answer 1: You would need to implement something like a switched rack PDU that would give you remote control to toggle power to the outlet that is powering the X serve.

Answer 2: If the UPS is off, power is cutoff, therefore the XServe cannot power itself up.

[EZ_Button_apc]

If you just let the battery drain all the way down, the UPS will obviously shut off. When power is restored, the UPS will begin to charge, but will not turn on to provide power.

You will need to configure PCNS to turn off the UPS after the shutdown finnishes. This will put the UPS into sleep mode, which will turn off power on the output of the UPSand then when power returns, it will wake up and provide power to your servers.

[Anonymous user]

Thank you both for your replies.

We have two Xserves running PCNS. Should I configure PCNS on both Xserves to turn off the UPS, or just one of them?

In the former case, my guess is that the UPS will turn off as soon as the first of the Xserves sends the turn off signal. Which could cause problems if the 2nd Xserve hasn't shut down before the UPS switches itself off.

The UPS has a setting called "Shutdown Delay" at 90 seconds, which I guess is the amount of time that the 2nd Xserve has to shut down after the 1st Xserve has given the turn off signal to the UPS.

In the latter case, I guess I could configure PCNS on one of the Xserves to shut down the Xserve after 10 minutes without giving the turn off signal to the UPS, and the other Xserve to shut down after 15 minutes and then give the turn off signal to the UPS.

But in both cases, because the servers have shut themselves down, they will not power up automatically in this setup? In other words, the "power on automatically after a power failure" setting of Mac OS X only applies if power is suddenly lost without a graceful shutdown?

[Cap1_apc]

The UPS will wait for confirmation from all of it's clients before starting it's own shutdown process. This means it'll start shutting down after seeing your second server send a shutdown confirmation.

Shutdown delay is a built in timer for the UPS to wait after it receives a shutdown command...this is basically a safety net for your load.

It depends on the BIOS setting, but most likely (from what you've already said) your servers will power back up when the power returns. Power MUST first be cut to the servers for this to work, which means the UPS must complete its graceful shutdown.

[BillP]

with no software nor a network management card, if the UPS shuts down due to a low battery (which is 2 minutes if batt power left), shouldnt it turn back on afterwards? the default setting for any UPS is "reboot on line return" unless someone has changed this via software or management card.

am i wrong on that? i tested a symmetra with no configured management card and no PCNS clients. it shutdown due to low battery and when the power was restored, it powered right back on, saying shutdown due to low battery, and turned the load back on.

shouldnt it be the same deal with this one? as long as the BIOS settings are correct, they should turn back on because the UPS should be providing power.

[BillP]

it should be true with all of APC's UPSs..

its just the fact that the UPS is on battery power and the server shuts down. so the server is turned off but there is still battery power available so when the utility power comes back, the server never really sees a chance in the power because there was either battery or utility power. the UPS would have had to shutdown and come back on to produce a change in state to it's output.

[Anonymous user]

>
The UPS will wait for confirmation from all of it's clients before starting it's own shutdown process. This means it'll start shutting down after seeing your second server send a shutdown confirmation.
Thank you. That bit of information is very helpful.

It depends on the BIOS setting, but most likely (from what you've already said) your servers will power back up when the power returns. Power MUST first be cut to the servers for this to work, which means the UPS must complete its graceful shutdown.

I hope this means that the Xserves, when shut down by PCNS, are shut down in a "special way", which causes them to automatically boot up again once power is restored to the UPS after the UPS has shut down. Maybe some "help I was shut down because of power failure" flag is set by PCNS?

Thanks for all the help!

It seems that testing is, as always, necessary to find out if what you think will happen actually happens.

Message was edited by: audunr

[BillP]

PCNS gracefully shuts down the machine. the BIOS needs to be set to last state for this machine to come back on after the UPS has been shutdown and restarted.

[refer to this link|http://nam-en.apc.com/cgi-bin/nam_en.cfg/php/enduser/std_adp.php?p_faqid=1191]

so after reading that, the only issue you may run into is if the ups goes to battery, and the server shuts down and then the power is restored. the server will already have been shutdown but the UPS hasnt rebooted. in this case, you will need to manually restart the server.

[Anonymous user · Accepted solution]

>
so after reading that, the only issue you may run into is if the ups goes to battery, and the server shuts down and then the power is restored. the server will already have been shutdown but the UPS hasnt rebooted. in this case, you will need to manually restart the server.
Yes, that's what happened in my first test. I was hoping that the UPS could reboot automatically when power returns, as it is suggested in one of the threads I linked to in my first post. But I guess that isn't possible with the model we have.

Message was edited by: audunr