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Questions tagged [electrical-power]

Power is required for all our servers, desktops, and other electronic devices to operate.

Power is required for all our servers, desktops, and other electronic devices to operate.

438 questions
249
votes
14 answers

What is this very short power cable called?

I have a couple of networking components in my rack that take giant AC adapters ("power bricks") that don't fit neatly into my rackmount PDU. I have one "thingy" that is shown below, and I need to buy a few more. But I have no idea what I'm…
Portman
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56
votes
6 answers

Why do we still use power supplies on datacenter servers?

Computers mainly need three voltages to work : +12V, +5V and +3,3V, all of them are DC. Why can't we just have a few (for redundancy) big power supply providing these three voltages to the entire datacenter, and servers directly using it ? That…
user186340
56
votes
4 answers

Assessing equipment damage following a lightning strike - Should I have planned more?

One of my client's sites received a direct lightning hit last week (coincidentally on Friday the 13th!). I was remote to the site, but working with someone onsite, I discovered a strange pattern of damage. Both internet links were down, most servers…
ewwhite
  • 201,205
56
votes
14 answers

Is UPS worthwhile for non-production equipment?

Over the years, I've had to throw away a quite a few bits of computing equipment (and the like): Several ADSL routers with odd symptoms (losing wireless connections, losing wired connections, DHCP failures, DNS symptoms etc) Two PVRs spontaneously…
Jon Skeet
  • 5,087
54
votes
5 answers

ipmitool - can't find /dev/ipmi0 or /dev/ipmidev/0

Based on a previous question, I installed ipmitool (yum install ipmitool). Even after a reboot, though, i get the following error when trying to run ipmitool power status: Could not open device at /dev/ipmi0 or /dev/ipmi/0 or /dev/ipmidev/0: No such…
warren
  • 19,297
51
votes
5 answers

PDU wiring - is this normal (or even safe)?

I removed the side panel of our server rack so I can clean up some of the wiring. Inside I found the PDU was wired like in the picture. Instead of an incoming power cable, there's just 3 uninsulated spade connectors. Is there any reason for wiring…
Grant
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43
votes
10 answers

Does CPU power management affect server performance?

I was doing some simple hand benchmarking on our (live) database server during non-peak hours, and I noticed that queries returned somewhat erratic benchmark results. I had enabled the "Balanced" power saving plan on all our servers a while ago,…
Jeff Atwood
  • 13,264
43
votes
6 answers

How do I permanently disable Linux's console screen saver, system-wide?

I've got an Ubuntu server that boots up in text mode. It rarely has a screen or keyboard attached to it, but when I do attach a screen, I usually have to attach a keyboard too, because the darn console mode screen saver will be on and I'll need to…
raldi
  • 997
42
votes
3 answers

How do servers with redundant power supplies balance consumption?

I have several servers from the HP DL360 line (generations 5-8). Each of these servers has two power supplies installed. The 2 power supplies in each server are fed from different circuits. My question is will the power draw be roughly balanced…
Travis Beale
  • 531
35
votes
9 answers

UPS and power strip interactions?

Sometimes I hear that you shouldn't plug (UPS brand X / any UPS) into (power strip brand X / any power strip) because of some interaction leading to poorly conditioned power, reduced battery life, massive explosions spattering the room with battery…
chaos
  • 7,533
29
votes
2 answers

Disable CPU Scaling in Windows Server 2008 R2

How do you disable CPU power management scaling in Windows Server 2008 R2? After setting the Control Panel, Power Management plan to performance and then rebooting -- CPUID's Cpu-Z still shows the clock speed being scaled.
Kyle Brandt
  • 85,693
28
votes
5 answers

How to build and run a machine room?

The last guy quit (I think a lot of adventures begin this way?) and I've been given the job to build a new machine room. I am coordinating with 2 engineers, campus ITS, campus Facilities Management, a project manager, a construction company and 2…
Fixee
  • 658
26
votes
4 answers

How to disable all power management in Ubuntu (for a server netbook)?

I need to disable everything related to having the netbook-server go into sleep/hibernate/shutdown. Spinning down the disks during inactivity is fine, but it is crucial that the machine remain in a state where it maintains connectivity over wi-fi…
adewinter
  • 371
25
votes
6 answers

Best practices for power cabling racks in DC

With network cables it is easy. I use velcro-ties, coloured cables, 0U vertical cable organizers from APC on side of the rack -- easy and neat. However with power cables it was always giving me headaches. With some of the racks I am using Vertical…
bart613
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20
votes
3 answers

Is there a way to protect SSD from corruption due to power loss?

We have a group of consumer terminals that have Linux, a local web server, and PostgreSQL installed. We are getting field reports of machines with problems and upon investigation it seems as if there was a power outage and now there is something…
Yehosef
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