UPS and Redunant power supplies

[rkirmeier]

My company has @25 NT servers which most are being protected by a large APC Symmetra UPS. I am reviewing the current setup and working on some recommendations. Most of our servers have 2 or 3 power supplies, it is my understanding that these are only for redundancy and not load balancing (Compaq & HP servers: please correct me if wrong). My question is; What is the best/recommended way to connect these servers to the UPS? If I connect all the power supplies to the APC Symmetra it decreases the run time so I am wondering if one should connect the extra 1 or 2 power supplies to a smaller UPS (for surge protection only) and fully rely on the Symmetra for power outages. I am assuming the smaller UPSs would run out of power very quickly... Anyone with any experience and/or insight on this suggect please forward your opinions or experience. If you know of any articles the discuss such informaiton please forward the link..

Thanks much,
RK

 

[jimbopalmer]

We put one in the wall and one in the UPS, that way when the UPS needs service (and it does every 6 months) our servers stay up I tried to remain child-like, all I acheived was childish.

 

[rkirmeier]

I guess this anwsers the question but you should never plug any equipment directly into a wall outlet without some protection (surge/spike)..

Anyone else have experiences with this?

Thanks..

 

[josepablomir]

Redundant Power Supply

This kind of devices can share load (load balancing) or not, depending on specifications. For example, Compaq offer different redundant power supplies, with hot plug and N+1 redundancy for different server models, for example some ProLiant models (I don’t know about HP but it seems hard to believe that this is not it’s case too).
If you plan to connect some power supplies to the UPS Symmetra, and some others to the wall outlet (with or without surge suppressors or any kind of filter or voltage regulator) you must keep in mind that in the occurrence of a blackout your UPS will deliver the full power to the server farm, so this is not a way to extend the system battery run-time.
Depending on the needs of your organization about availability and performance you should consider adding additional UPSs to the system to improve it. You could use extra battery packs (APC offers it for Symmetra systems); or you could add additional UPSs; or switch to a different topology like Hot Redundant.

Regards,

Jose P. Mir
jpm@jpmir.net

_________________
Jose P. Mir
jpm@jpmir.net