Datacenter, Symmetra and PCNSD

[Anonymous user]

Hello all!!!

I just got my first datacenter up and running.  We have 2 hosts, shared storage and a APC Symmetra.  I have the PCNSD ova installed in my cluster and it is talking to my APC.  I went through the setup and basically stuck with the defaults on how to handle the VMs.  My UPS says it will run for 40min on battery.  I would like to start the process of a shutdown at 10min (25%) run time left.  The settings on the device (APC) and the appliance have me a little confused.  Maybe someone could help me out?

This is how my APC is configured:

Start of Shutdown

Low Battery Duration = 10 mins

Shutdown Delay = 20secs

Basic Signaling = Enabled

PowerChute Shutdown Parameters

Max Req Delay = 10 min

Now in my PCNS server:

Shutdown Settings:

Dont turn off UPS

VM settings

Dont Migrate

VM Shutdown 120 secs no start up

vCenter Shutdown 240 secs

In Configure Events in PCNS and Im thinking I need to set Runtime remaining below thresholds Shutdown settings.  When you enable that it alows you to edit the Threshold.  What is this threshold?  Is it not listening to the 10min that I set on  the UPS?  Is this in addition to that?  Do I set that to 600 (10x60) ?  Its not very clear what that is.

Do my PCNS and UPS settings look ok?  Also is there a graceful way to test this out other then pulling the plug and waiting a half hour?

Thanks in advance!

[BillP]

Hello,

With what you have configured now when the UPS has 10 minutes of battery left (low battery) it will send a signal to PowerChute and VMs / host shut down will start.

If you are looking for descriptions of the event actions you can review the users guide (starting on page 75) or click on the question mark on the PowerChute web page to launch help file.

Here is the description of Runtime remaining below

• When the UPS is running on battery power and the runtime remaining on the UPS drops below the threshold, PowerChute will trigger a shutdown sequence. 

If you are going to configure Runtime remaining below threshold I suggest it be greater than Low Battery. Since you need 120 second for the VMs and 240 for vCenter I would set Runtime remaining below threshold to 1080 seconds. 10 minutes for low battery, VM shut down, vCenter shut down, plus 2 minutes = 18 minutes or 1080 seconds.

With that setting when the UPS battery fails below 18 minutes PowerChute will start the shut down process.

[Anonymous user]

Thanks for getting back to me Bill:

So if I understand.  Right now my UPS is going to shutdown at the 10 min power remaining mark.  If I dont adjust the threshold on the PCNS event "Runtime remaining below threshold" there will be no time to shut down theVMs.  On the APC under the PowerChute settings there is:

Maximum Required Delay:

10 minutes

What is that?

I know your not supposed to run the batteries all the down,  so what is a safe number on when to shut it down?

Where is the best place to start the VM shut down?

[BillP · Accepted solution]

With the UPS set with Low battery at 10 minutes the UPS will send a signal to PCNS when the UPS has 10 minutes of runtime and PCNS will start the VM, Host, and OS shutdown (in that order). The UPS will not power down until the battery is drained. As long as it does not take longer then 10 minutes for the VMs, Host, and OS to power down gracefully everything will be fine. If it takes longer then that amount of time the low battery time frame should be increased.

Here is the description of Maximum Required Delay from the NMC help file

Maximum Required Delay

Calculates the delay needed to ensure that each PowerChute client has enough time to shut down safely when the UPS or the PowerChute client initiates a graceful shutdown. Maximum Required Delay is the longest shutdown delay needed by any server listed as a PowerChute Network Shutdown client. This delay is calculated whenever the management interface of the UPS turns on or is reset, or when "Force Negotiation" is selected as Maximum Required Delay. "Force Negotiation" polls each client for information on the time it needs for a graceful shutdown. Two extra minutes to allow for unforeseen circumstances is then added to the calculated time. The negotiation can take up to 10 minutes. If you do not select "Force Negotiation", two minutes is used by default as the shutdown delay for all clients.

What that means is when you add VM, vApp, VCSA, and command files delays the NMC is given that information. The NMC add up all that time and enters it as the Maximum Required Delay so that the UPS knows it need that amount of time to ensure the each PowerChute client is shut down gracefully.

Example: VM shutdown delays of 120, vCenter Server delay of 240 = 6 minutes plus 2 additional non configurable minutes = 8. With those numbers the low battery and maximum required delay should be 10 minutes.

As I wrote earlier if you are going to configure Runtime remaining below threshold I suggest it be greater than Low Battery. Since you need 120 second for the VMs and 240 for vCenter shutdown and are not including VM start up I would set Runtime remaining below threshold to 1080 seconds. 10 minutes for low battery, VM shut down, vCenter shut down, plus 2 minutes = 18 minutes or 1080 seconds. This way the UPS never gets to low battery.