Slashdot Mirror

← Back to Stories (view on slashdot.org)

When Does Powering Down Servers Make Sense?

Posted by timothy on 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?"

3 of 301 comments (clear)

  1. Virtualize! Virtualize! Virtualize! by Anonymous Coward · · 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 nabsltd · · 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?

  2. Re:Business needs and Risk by vwjeff · · 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.