When Does Powering Down Servers Make Sense?

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When Does Powering Down Servers Make Sense?

Posted by timothy on Thursday October 30, 2008 @07:35AM from the after-coffee-is-served-of-course dept.

snydeq writes "Powering down servers to conserve energy is a controversial practice that, if undertaken wisely, could greatly benefit IT in its quest to rein in energy costs in the datacenter. Though power cycling's long-term effects on server hardware may be mythical, its effects on IT and business operations are certainly real and often detrimental. Yet, development, staging, batch processing, failover — several server environments seem like prime candidates for routine power cycling to reduce datacenter energy consumption. Under what conditions and in what environments does powering down servers seem to make the most economic and operational sense, and what tips do folks have to offer to those considering making use of the practice?"

17 of 301 comments (clear)

Only when it makes sense by Yvan256 · 2008-10-30 07:37 · Score: 5, Funny

Like when someone posts your domain name on slashdot!
You can't take down a server that's already off-line.
1. Re:Only when it makes sense by TubeSteak · 2008-10-30 08:43 · Score: 5, Funny
  
  You can't take down a server that's already off-line.
  Nuke the entire site from orbit.
  It's the only way to be sure.
  
  --
  [Fuck Beta]
  o0t!
Simple by eln · 2008-10-30 07:40 · Score: 5, Funny

The best time to shut down the servers is right before you quit your job. Password-protecting the BIOS first adds value too.
1. Re:Simple by Anonymous Coward · 2008-10-30 08:50 · Score: 5, Funny
  
  Password-protecting the BIOS first adds value too.
  A real pro puts epoxy on the BIOS battery & any motherboard jumpers.
  If I can't have this server, neither can you
2. Re:Simple by mysidia · 2008-10-30 11:36 · Score: 5, Funny
  
  A real blackhat flashes a custom BIOS with the password set, so pulling the battery just resets the BIOS back to his default password.
WOL by Anonymous Coward · 2008-10-30 07:41 · Score: 5, Insightful

Put redundant/failover servers into a sleep state and enable WOL.
1. Re:WOL by cerberusss · 2008-10-30 23:38 · Score: 5, Funny
  
  Mod parent redundant.
  
  --
  8 of 13 people found this answer helpful. Did you?
I go by a few simple rules... by Anonymous Coward · 2008-10-30 07:41 · Score: 5, Funny

I'm glad this was posted to "Ask Slashdot" where your audience is highly seasoned professionals that can give you wise, insightful answers...
In the data center that I manage, I use a few simple rules to determine when I power them down.
1) If the server is on fire
2) If there are no users using the server
or
3) If the power company is saying that I haven't paid my bill and they are sending "Hank" over to cut me off
4) Civil unrest, tornado, earthquake, zombies, etc.
1. Re:I go by a few simple rules... by Anonymous Coward · 2008-10-30 08:19 · Score: 5, Funny
  
  I'm glad this was posted to "Ask Slashdot" where your audience is highly seasoned professionals that can give you wise, insightful answers...
  In the data center that I manage, I use a few simple rules to determine when I power them down.
  1) If the server is on fire
  2) If there are no users using the server
  or
  3) If the power company is saying that I haven't paid my bill and they are sending "Hank" over to cut me off
  4) Civil unrest, tornado, earthquake, zombies, etc.
  Zombies aren't a good reason for shutting down the servers, that's why our IT guy keeps a shotgun leaned up against the server....at least he says it's for zombies.
Virtualize! Virtualize! Virtualize! by Anonymous Coward · 2008-10-30 07:43 · Score: 5, Interesting

If you virtualized your servers, you could create a managed power-down/power-up scenario. In the morning, your servers would turn on, your virtualized instances would move around (so they have more power for the day's activities), and then at night they'd retreat to a smaller group of servers. The unused servers could shut down for the night. You could even rotate which servers stay on overnight keeping the virtual servers running to spread the wear around if there is some.
1. Re:Virtualize! Virtualize! Virtualize! by Amarok.Org · 2008-10-30 08:00 · Score: 5, Informative
  
  There are a number of tools and products out there to assist this.
  Consider a large (65k+ employees) company that has a several hundred server implementation that they use to process payroll every two weeks. They use a management tool to power them up on Friday, process payroll over the weekend, and shut them down on Monday. The power and cooling cost impact of these several hundred servers *not* running most of the month (6 or so days a month instead of 31) is huge.
  Another (and also in use by the same company) strategy is to virtualize the OS instances, spin those up and down as necessary, and then use something like VMWare's VMotion to maximize usage of the physical boxes - and again use another tool to power down unneeded compute capacity.
  Welcome to the virtual world...
  Lots of prerequisites, but when it works, it's pretty freakin' sweet...
  
  --
  -- "Other than that, how was the play Mrs. Lincoln?"
2. Re:Virtualize! Virtualize! Virtualize! by nabsltd · 2008-10-30 08:57 · Score: 5, Interesting
  
  First, let's assume "several hundred" equals 200, and we have exactly 65000 employees. Let's also assume that these extra servers are on for exactly 48 hours. Let's also assume perfect load balancing and distribution of the process over the servers.
  That means that each server processes payroll for 325 employees in 48 hours, or about 7 employees per hour. So, each of these servers is basically the equivalent of a Commodore 64 in computing power. I suggest that the best way to save money at this task is to replace the 200 servers with a single Pentium 4 quad core running at 3GHz.
  The other explanation—that the software is so unbelievably bad that it really does take 8½ minutes for it to run a single employee—is possible, but would going out and buying "QuickBooks" really cost more than the 200 servers to run this awful beast of a payroll program?
3. Re:Virtualize! Virtualize! Virtualize! by billcopc · 2008-10-30 11:45 · Score: 5, Funny
  
  First of all, I'm with you, I also don't understand what it is about these mythical accounting processes that takes so damn long to process.
  I guess it's like everything else in the software industry:
  - software built by programmers for programmers runs quickly
  - software built by programmers for non-programmers is incoherent
  - software built by non-programmers for non-programmers is slow as molasses
  - software built by non-programmers for programmers is never executed!
  
  --
  -Billco, Fnarg.com
Re:The moment when.... by Yvan256 · 2008-10-30 07:47 · Score: 5, Funny

Give it 30 seconds and it'll do it on its own (sorry couldn't resist either)
Re:Well... by csnydermvpsoft · 2008-10-30 07:50 · Score: 5, Insightful

What kind of UPS does that? If the batteries are already charged, what would it be doing with the power that's not consumed by the devices - does it also act as a space-heater?
The ratings for UPS's - and any other power supply - are peak loads, if the UPS is being used at 100% capacity.
Re:Business needs and Risk by vwjeff · 2008-10-30 08:26 · Score: 5, Interesting

Example Setup The organization I work for has a well known usage patterns that we use to make decisions like this. 95% or more of our traffic occurs during business hours which we define as 7:00 AM - 7:00 PM. During business hours we have dedicated servers for various functions. We have a cluster of servers running virtual server instances that duplicate the dedicated servers. During off hours the dedicated servers are powered down and the virtual server instances take over. It works for us and we have seen a significant decrease in power usage with no impact on our users.
Re:Well... by prog-guru · 2008-10-30 08:51 · Score: 5, Funny

(My datacenter charges about a buck a VA)
A watt?

--
chris@xanadu:~$ whatis /.
/.: nothing appropriate.