Using two Smart UPS X-3000 and servers with dual power supplies to extend up time

[kds86_apc]

I have two Smart UPS X-3000 units and four host servers (3 in a VMware cluster and 1 a Linux server). Each of the servers have dual (redundant powers supplies), and I have one power supply from each server plugged into to one of the X-3000's, and the other power supplies plugged into the second X-3000. It occurred to me the other day that in this scenario we could almost double our up time if we could have one X-3000 carry the servers until reaching a critical battery state, then trigger/transfer to the other X-3000 to carry the servers' other power supplies until either it runs out of battery power or line power is restored.

Is there a way to configure these X-3000s to do this, and if yes, how? 

Thanks for your assistance,

Kevin

[BillP]

Hi Kevin - 

Unfortunately there is no real way to do this with the Smart-UPS, as they will both switch to battery when they lose input power. The way we work with extended runtime is by supporting external battery packs. By adding external packs you will extend your runtime while maintaining a full redundant solution. 

[kds86_apc]

Thank you for your reply, Liam!

Do you know of any other APC units of comparable capabilities to these X-3000's that does offer what I described as wanting to do?

[voidstar_apc]

It's not supported by APC but in theory if your dual supplies are set up so only one is active at a time (ie, it has a preferred source), it'll drain the first UPS and then drain the second one. You'll want to use the second UPS to trigger safe shutdown.

Part of the problem though is that both UPSes will go on battery so they can continue to operate after the power fails. So you won't get double the runtime this way... the second UPS battery will have partially drained before your server switches over to it.

Because of that and additional failure modes, I agree with Liam: extended run batteries would be a safer bet. Your SmartUPS X has a blue connector on the back to accept them.

[kds86_apc · Accepted solution]

Thanks voidstar for your input as well! 

I will consider the extended run batteries as a way to get more up time. 

Thanks again to both of you!