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113

I would just call it a "very short extension cord", and in fact a Google search for "short extension cord" turns up lots of results of exactly what you're looking for. E.g., these, which have a pass-through plug.


53

What'cha talking 'bout Willis? You can get 48V PSUs for most servers today. Running 12V DC over medium/long distance suffers from Voltage Drop, whereas 120V AC doesn't have this problem┬╣. Big losses there. Run high voltage AC to the rack, convert it there. The problem with 12V over long distance is you need higher amperage to transmit the same amount of ...


44

"pigtail" is a common term for these (actually any 6" to 1' power cord) in the datacenter environments I've worked in.


42

Short answer, yes. Long answer, read this: http://www.codinghorror.com/blog/archives/000632.html


39

That's shockingly bad (sorry!). If that cable gets yanked out by someone, at the very best it will short out and hopefully trip the circuit breaker, possibly taking out power in other racks or even other parts of the building. Worst case, somebody could be killed. Personally I'd do the following: Carefully secure the rack. Lock it up, post a notice to ...


34

I did some stats on this a while ago FWIW, using the handy dandy kill-a-watt.. Typical Developer Dell PC (2.13 GHz Core 2 Duo, 2 GB RAM, 10k RPM 74 GB main hard drive, 7200 RPM 500 GB data drive, Radeon X1550 video) Sleep 1 w Idle 80 w One CPU core fully loaded 108 w Both CPU cores fully loaded ...


34

You can also get short Y power cords. These cables (including the single variety) are sometimes called "outlet savers". I also love the 90┬░ rotating plug variety for some applications. The cord goes flat against a wall.


33

I'm going to give an HP-specific answer here, since the OP is asking about the ProLiant product line. Let's use the example of an HP DL360p Gen8 (also applies to G6 and G7 servers): You have the option to configure the Redundant Power Supply Mode in the HP Rom-Based Setup Utility (press F9 at boot) with: Balanced Mode High Efficiency Mode Of the two ...


32

Before the outage: Power everything off - workstations, servers, printers, switches, the works. Turn off your UPS' so they don't panic when power is lost. After outage in this order: Turn on UPS Turn on networking (router, switches etc) Turn on servers Turn on workstations Turn on everything else Have a test plan ready so you can test important ...


30

Having had some 'discussions' with the inspector that comes around our offices once a year to make sure we're not being bad, I have a better idea as to what code says about this. Paraphrased from said inspector: Thou shalt not plug a power-strip into another power-strip Nor any multi-outlet device into another multi-outlet device, for it is a fire-hazard, ...


23

You can plug in that many drives via USB . . . but I wouldn't recommend it. The single biggest issue you're going to run into is the use of USB 2.0 (480Mb/sec shared across all devices on the controller). Unless you're using USB 3.0, you are going to seriously limit your disk throughput. USB was intended for temporary (hot plug) or situations where very ...


22

There are 3 Main BIOS settings in the Dell R710 that control this under Power Management: OS Control sets the CPU power to OS DBPM, the fan power to Minimum Power, and the memory power to Maximum Performance. In this setting, all processor performance information is passed from the system BIOS to the operating system for control. The operating system ...


22

You should be safe. It is always OK to put a lower load on a higher rated receptacle. (At the proper voltage that is. Don't mix 230V and 115V). Just think of it this way: If it wasn't OK nobody could plug a phone charger (about 2 Amp max) in a standard wall-outlet (10 Amps or more). And for the record: I am a qualified electrician. Even though it's been ...


21

The console-tools package allows console options to be controlled. To turn off screen blanking and powerdown, set BLANK_TIME and POWERDOWN_TIME to 0 in /etc/console-tools/config. If you'd prefer not to modify the config file, the same effect can be achieved by creating a new file in /etc/console-tools/config.d containing the following: BLANK_TIME=0 ...


20

A couple of jobs ago, one of the datacenters for the place I was working for was one floor below a very large aerial. This large, thin, metal item was the tallest thing in the area and was hit by lightning every 18 months or so. The datacenter itself was built around 1980, so I wouldn't call it the most modern thing around, but they had long experience ...


19

I think the official name is "Power Strip Liberator". Google image check: http://www.google.com/images?q=power+strip+liberator UPDATE: Sorry, I think that's a product's name (trademark), not the common name for the "thingy." But I looks like that the product is the "Coke" amongst power extension cords. :)


18

Sounds very much like the drives are doing SMART scrubbing (automatic online testing). smartctl -a /dev/hdx should confirm the configuration with: Auto Offline Data Collection: Enabled. Disable with: smartctl --offlineauto=off /dev/hdx It could be something else too...


18

I am no electrician either, but I think you will at least lose the possibility of keeping your server up and running when doing so. On the contrary if you connect each PSU to a different power source, your server will still have an availble power source (hopefully).


18

It's not necessarily more efficient as you increase the I^2R losses. Reduce the voltage and you have to increase current in proportion but the resistive loss (not to mention the voltage drop) of power cables increases in proportion to the square of the current. Thus you need massive, thick cables too, using more copper. Telcos use typically -48V so they ...


17

I'd worry about that. When you say uninsulated, do you really mean those are live and unprotected? If so, that's not safe. Find an electrician to help, and stay out of there while you do it!


16

It allows the raid card to remember what is in its buffers ( that hasnt been sync'd to disk ) Its very important for people who need high data integrity.. Or to save your DB from certain types of corruption.. (Basically whats on disk, is on disk - so thats safe.. The problem is when the OS thinks its on disk but its actually not and in a RAID card buffer) ...


15

I've never used them because they're a single point of failure, at best. Every server I deploy into a real datacenter has each PSU plugged into a different PDU in the rack, each of which are attached to a different independent UPS, on different circuits, ideally even fed from different power feeds. If the UPS, PDU or circuit your Y-cable's attached to goes ...


15

Or you use /etc/kbd/config to set up (depends on your system, what is installed) BLANK_TIME=0 BLANK_DPMS=off


15

You might want to distinguish between filtered power and uninterrupted power. Uninterrupted power is probably a good idea for things that you want to shutdown gracefully. Depending on your needs you might only need enough time for the shutdown to finish, resulting in a much cheaper UPS. Other devices may not need UPS at all, but only filtered power. ...


15

That is a fire (or electrical accident) waiting to happen. Nothing good can come of that. It is negligent and noncompliant and most definitely not normal. I'd imagine it wouldn't be a fun thing to try and explain to an insurance company either, in the event. I can imagine a dozen different scenarios in which that connection becomes a disaster either to ...


15

Why not just plug into a NEMA 5-15 or 5-20 receptacle? You don't need to use the L5-30 circuit. But yes, you can do this. It's possible to just buy an L5-30P-NEMA 5-15R pigtail adapter online or manufacture your own. However, I'm assuming you have plentiful 5-15 receptacles available to you. Is there a reason you can't use one of those instead?


14

Most of the time, there is a BIOS option for what to do when getting power back. You can set it to "Always on" or "Last State" or "Never power on" (or something like that). I prefer the second one.


14

You probably need to load the IPMI kernel modules: modprobe ipmi_devintf modprobe ipmi_si You can add these to /etc/modules to have them loaded automatically (just list the module names): ipmi_devintf ipmi_si


13

This is because that equipment was designed to be installed anywhere in the world, and not every place has 3-wire electrical. Additionally, not every 3-wire install has a well grounded ground-wire, so having the option of creating a separate ground is a very good idea for the enterprising electronics manufacturer. What is the impact of not using the ...


13

I've answered a similar question elsewhere. Constant cycling of the power on regular drives actually leads to premature drive failure. The drives are rated for only so many spinups/spindowns, and if you cycle them too frequently, the drive will start to exceed its rated capacity for this. Note that this assumes you're using desktop or server-style 3.5" ...



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