Is it possible to stagger the restart of servers using PCNS

[Anonymous user]

as of right now I think I have the PCNS clients shutting down properly, but when power is restored every machine in the racks are booting at the same time, including switches. I would like to stagger the reboots and give the switches a couple of minutes to initialize prior to the servers begning their reboot process. I thought maybe creating an execute command file event on power restore and the putting a delay prior to executing a "do nothing" command file might do it, but I am not sure and I dont see a good way to test that configuration.

We are experiencing a lot of power failures due to construction in the building and I would really like to get this addressed.

Thank you for any help.

[BillP]

Power Restored refers to when it is restored to the UPS, not the server so that wouldn't help you out. PCNS only deals with a shutdown in general.

To be honest, I feel like a Switched Rack PDU is your best bet and basically what the product is for. You can do what you asked for and stagger power on/off/reboot delays for each outlet. Our Switched Rack PDUs are here -> Switched Rack PDU - Product Information and we also have some Switched with Metering By Outlet if you wanted that (Metered-by-Outlet Rack PDU - Product Information).

Lastly, if you go to testdrive.apc.com, you can log into some of our Rack PDUs to check them out.

[Anonymous user]

Thank you for the response Angela. The Power restored I am refering do is an event on the client side. If it means when power is restored to the UPS then why is the event configurable on the client (i.e. execute command file)? How can the client do anything at the time power is restored to the UPS because technically the client doesnt get power until AFTER power is restored to the UPS, especially if you have things like minimum battery charge set at 5% set at the UPS.

[BillP]

Hi Matt

Let me give you an example on what I mean because I think there is some confusion.

UPS has 30 minutes of runtime. PCNS at default configuration to shutdown when UPS reaches low battery (by default with 2 mins runtime remaining)

10:00 -  AC power lost, UPS goes to battery, PCNS sees the event that UPS went to battery power (which is in a message from the UPS Network Management Card in the UPS)

10:20 - AC power restored. UPS is online (notified by UPS NMC again). PCNS client has not begin a shutdown yet since power loss was only 20 minutes. So, PCNS does not need to shutdown the system since power is restored and battery is charging.

Thus, when PCNS never is forced to shutdown the system, you could see power restored since PCNS monitors input status to the UPS among other events.

[Anonymous user]

That makes sense. Although it seems a fairly small application window for an event.

So i guess I will refer to your first response as your recommendations on how to address my need to control reboots.

Thank you

[BillP]

Not a problem but that is what the event is for. Some UPSs may have a large runtime i.e. several hours so when the power comes back on, perhaps a command file is executed to send a message via messenger service or to do something else. So, not many users use it but that is what its there for.

Let me know if you have any switched rack PDU questions.

[Anonymous user]

Actually Angela, we do have 2 metered PDUs already. Can those be configured to stagger reboots?

[BillP]

Unfortunately no. One of the main differences on Metered and Switched is individual outlet control and the functionality that comes along with that. Switched does encompass the ability of the metered though.

[voidstar_apc]

If using a SMX or SMT UPS, perhaps put the servers on a separate outlet group for the switches, and set a power on delay. Or with any UPS, plug the switches and servers into separate UPSes with different on delays.

[BillP · Accepted solution]

Good point voidstar. I forgot - SMT and SMX Smart UPS provide switched outlet groups and have similar functionality to outlets on a switched rack PDU except they are in a group.