UPS server wiring no-no

[Adrian C]

I spent a frantic ten minutes in the early hours of last night scrabbling around in the dark with wire cutters and a fading torch trying to patch in a LCD monitor and KVM switch to UPS power, the normal mains supply for them having previously failed due to a midnight team digging up the road outside. Happily I managed to do a proper shutdown of the protected servers before the UPS battery (and my torch) gave out.

If ye are ever enagaged in wiring up a server rack cabinet, can ye

a) Connect these low wattage items permanently to the UPS output, or... b) Put them on an obvious extension block and compatible inter-connector so they can be quickly unplugged and swapped from dead mains supply to UPS output?

I was pretty lucky to find random IEC leads and a spare 13A extension block in a cardboard box next to the rack. And a tool box...

Phew....

[Andy Burns]

... configure the UPS to cleanly shutdown all the servers it is powering.

[GB]

What if you had not been available at all? You need a better system for doing this.

[Rob Morley]

... wire a light into the UPS so you can see what you're doing?

Others have made more useful suggestions.

[Andrew Gabriel]

I remember doing this with Powerchute in the early days, and then have bugs in Powerchute close down the servers when there was no need. System availability went down (as often happens when you increase system complexity).

Nowadays (and actually, even back then), I run OS that doesn't care about the power being pulled with no notice, and where I have a UPS, I just leave the UPS to cut out if its battery runs flat without shutting down the OS. That's given me something that turns out to be very reliable, and increases system availability.

[Nightjar]

When I built a rack mount computer system for one of my businesses, I did what I always also do with electricity distribution boards - fitted an emergency light where it would provide enough light to see what I was doing. It was also configured to shut down automatically in case of mains failure.

Sounds like someone else had the same problem on a previous occasion.

Colin Bignell

[Andy Burns]

With older APC with serial connections maybe, though I don't remember it happening lately.

What I've done more recently (with large Chloride UPSes powering multiple racks of VMware boxes and SAN kit) is react to SNMP traps so shutting down unnecessary VMs when power outage has existed longer than a couple of minutes, then corral the remaining VMs onto fewer physical servers, shut down the unused physical servers, rinse and repeat the process with more and more important servers to preserve power for the most critical VMs and storage for as long as possible ...

Yes, it's even more complex ...

[John Rumm]

Something I routinely do when fitting a consumer unit these days...Only adds £15 to the cost, ans is so much easier!

[Grimly Curmudgeon]

My LCD, network routers/hubs/switches for LAN and USB are all powered from the UPS, to give any file-saving activity a chance to finish or wrap up losslessly, with any luck. The UPS breathed a sigh of relief, no doubt, as it was previously running a CRT in the same configuration. Only drawback with that was the start-up surge on switch-on.

[newshound]

I've just got a little torch and a volt stick resting on top of mine

[Andy Champ]

Well, I hope they've all got dual PSUs with the second one fed straight from the mains? You wouldn't want a UPS fail to take all your systems down...

Andy

[Grimly Curmudgeon]

On balance, hardly worth it. The number of mains failures in the past decade = 50 UPS failures = 0

[Fred]

[Huge]

It being Andrew, it'll be Solaris.