# Building 1U Rails Server - Power Calculations? **URL:** \ **Category:** Deployment\ **Created:** [March 1, 2008, 11:06am UTC](https://www.ruby-forum.com/t/building-1u-rails-server-power-calculations/130655 "2008-03-01T11:06:03Z")\ **Posts on this page:** 15\ **Page:** 1
**Author:** ![softf5ajivanet](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/s/9f8e36/32.png) [@softf5ajivanet](https://www.ruby-forum.com/u/softf5ajivanet)\ **Post date:** [March 1, 2008, 11:06am UTC](https://www.ruby-forum.com/t/building-1u-rails-server-power-calculations/130655/1 "2008-03-01T11:06:03Z")
Hi all, With all the mini-apps i’m writing I’ve decided to build my own 1U rack server, but need a few pointers on calculating power consumption. Basically the colocation place i’ve selected for the device has a limit of 0.5 Amps of power per box, so need to keep the power down below that limit otherwise it’ll cost more to host. A friend of mine is doing the same, I can build and setup the system myself but never mastered power calculations at school so a bit alien to me working out power load, etc. 😉 I’m going to be using something like… CPU: AMD 64 chip [heard they’re good for lower power + speed] O/S: Fedora 8 [works well with AMD cpu’s low-power state] HDD: 2x SATA2 WD Drives [500gb each, in a RAID 1 config] MEMORY: 2x 2GB sticks [samsung brand, been using then all the time, reliable] MOTHERBOARD: ASUS standard ATX mb [always found ASUS reliable] Case-wise I’ve found a couple on ebay so will try and snag one this week. PSU: hunting around for good reliable PSU, but most only operate at 50-60% capacity, sort of wanting it running at 80% if i can. The company I’ve chosen is [http://www.rapidswitch.com/](http://www.rapidswitch.com/) up the road from where I live, £32 a month (which is less than the $100+ dollars i’m paying my current colo to run my virtual boxes, and I’m kinda looking forward to doing this myself). Gotta keep it down to 0.5A Any ideas how to do the power calculations greatfully received, ---
**Author:** ![softf5ajivanet](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/s/9f8e36/32.png) [@softf5ajivanet](https://www.ruby-forum.com/u/softf5ajivanet)\ **Post date:** [March 1, 2008, 11:12am UTC](https://www.ruby-forum.com/t/building-1u-rails-server-power-calculations/130655/2 "2008-03-01T11:12:21Z")
Ok, using DELL’s power calculator I worked out… 0.5A =\> 120Watts. so a nice bit of legroom, now hardware? ---
**Author:** ![softf5ajivanet](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/s/9f8e36/32.png) [@softf5ajivanet](https://www.ruby-forum.com/u/softf5ajivanet)\ **Post date:** [March 1, 2008, 8:30pm UTC](https://www.ruby-forum.com/t/building-1u-rails-server-power-calculations/130655/3 "2008-03-01T20:30:10Z")
for me, it’d probably be about 5 rails sites with about 7 mongrel clusters spread over these, then a php website my fiancee’s building for a friend at work, and then probably a load more. as this’d give me a server with less limits than your average setup from the third-party and total control so i could get it exactly how i want it, the flexibility and extra experience would be pretty invaluable; hence the decision. hope this helps. ---
**Author:** ![softf5ajivanet](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/s/9f8e36/32.png) [@softf5ajivanet](https://www.ruby-forum.com/u/softf5ajivanet)\ **Post date:** [March 1, 2008, 11:58pm UTC](https://www.ruby-forum.com/t/building-1u-rails-server-power-calculations/130655/4 "2008-03-01T23:58:16Z")
Something to keep note is: More RAM = more juice… 7 mongrel clusters is a minimum of 1.5 GB of ram, right? (with headroom) You’d want a little more for the system - db etc. 120 watts isn’t a stupid amount of power by any stretch… On Mar 2, 6:30 am, John G. [removed\_email\_address@domain.invalid](mailto:removed_email_address@domain.invalid) ---
**Author:** ![softf5ajivanet](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/s/9f8e36/32.png) [@softf5ajivanet](https://www.ruby-forum.com/u/softf5ajivanet)\ **Post date:** [March 2, 2008, 12:02am UTC](https://www.ruby-forum.com/t/building-1u-rails-server-power-calculations/130655/5 "2008-03-02T00:02:17Z")
couldn’t agree more, that’s why i’m researching like mad to get things right first time. looks like most things will be a custom job, will let you know how it goes. All the best, John. ---
**Author:** ![softf5ajivanet](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/s/9f8e36/32.png) [@softf5ajivanet](https://www.ruby-forum.com/u/softf5ajivanet)\ **Post date:** [March 1, 2008, 1:15pm UTC](https://www.ruby-forum.com/t/building-1u-rails-server-power-calculations/130655/6 "2008-03-01T13:15:08Z")
Just curious: How many "mini-apps? How much traffic? What is your current configuration? How much resources are these apps consuming? – Aníbal Rojas > **[Home - Has Many Developers](https://hasmanydevelopers.com/)** > > We are the best choice for your building design and development http//rubycorner.com On Mar 1, 6:06 am, John G. [removed\_email\_address@domain.invalid](mailto:removed_email_address@domain.invalid) ---
**Author:** ![softf5ajivanet](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/s/9f8e36/32.png) [@softf5ajivanet](https://www.ruby-forum.com/u/softf5ajivanet)\ **Post date:** [March 2, 2008, 1:01am UTC](https://www.ruby-forum.com/t/building-1u-rails-server-power-calculations/130655/7 "2008-03-02T01:01:45Z")
On Mar 1, 2008, at 2:06 AM, John G. wrote: > that > AMD 64 chip [heard they’re good for lower power + speed] > > O/S: > Fedora 8 [works well with AMD cpu’s low-power state] > > HDD: > 2x SATA2 WD Drives [500gb each, in a RAID 1 config] Just a side note. When you setup the machine… I’d _highly_ recommend setting up separate XEN instances. We do this for a lot of our Managed Hosting customers at Planet Argon. Basically, we install the base OS (Linux… usually Debian) with XEN and then isolate the various pieces of the application for future scaling needs. 1 - Web server that balances to the app servers 1 - Database server (+1 if you have resources to setup a replication db xen instance) 2-3 - App servers (nginx + mongrel clusters) 1 - Asset server (memcached, images, etc…) This ends up working nicely and is a good starting point for future scaling needs. Robby – Robby R. Founder and Executive Director PLANET ARGON, LLC Design, Development, and Hosting with Ruby on Rails > **[Planet Argon](https://www.planetargon.com/)** > > Planet Argon is a Ruby on Rails development agency specializing in maintenance and support for existing Rails apps. Based in Portland, OR, Planet Argon has been a member of the Rails community since 2004. [http://www.robbyonrails.com/](http://www.robbyonrails.com/) aim: planetargon +1 503 445 2457 +1 877 55 ARGON [toll free] +1 815 642 4068 [fax] ---
**Author:** ![softf5ajivanet](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/s/9f8e36/32.png) [@softf5ajivanet](https://www.ruby-forum.com/u/softf5ajivanet)\ **Post date:** [March 2, 2008, 12:10am UTC](https://www.ruby-forum.com/t/building-1u-rails-server-power-calculations/130655/8 "2008-03-02T00:10:02Z")
one thing… any ideas how to judge power consumption for memory sticks and how much power a motherboard will consume? can’t find any technical data on the corsair memory sites anywhere, and not sure how to judge power requirements for the board. ? ---
**Author:** ![softf5ajivanet](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/s/9f8e36/32.png) [@softf5ajivanet](https://www.ruby-forum.com/u/softf5ajivanet)\ **Post date:** [March 2, 2008, 11:25am UTC](https://www.ruby-forum.com/t/building-1u-rails-server-power-calculations/130655/9 "2008-03-02T11:25:37Z")
Yes, Robby is right on this one too. I was going to comment about Xen also, but I thought I’d let you get the hardware part right first. Not sure about memory consumtion on specific chips or anything… the best thing to do is to contect your vendor and let them do the homework. Its not going to cost any extra and it’ll save you the time! ---
**Author:** ![softf5ajivanet](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/s/9f8e36/32.png) [@softf5ajivanet](https://www.ruby-forum.com/u/softf5ajivanet)\ **Post date:** [March 2, 2008, 4:01pm UTC](https://www.ruby-forum.com/t/building-1u-rails-server-power-calculations/130655/10 "2008-03-02T16:01:05Z")
> Basically the colocation place i’ve selected for the device has a limit > of 0.5 Amps of power per box, so need to keep the power down below that > limit otherwise it’ll cost more to host. > > … > Any ideas how to do the power calculations greatfully received, 0.5A seriously? Yikes that is not a lot of power for a server, that’s only 120 Watts (240 V \* 0.5A = 120 watts). The low end server you’ve specified (AMD CPU, 4 sticks of RAM, standard motherboard etc) is easily going to draw 120 W when idle, at load its going to be more like 300. A modern AMD CPU will be 80W on its own, then the 1GB of RAM is 10 W (40W), the motherboard is often 40-60W, hard drives are roughly 20W, you are massively over your power budget even with this basic machine setup. I can think of 2 configurations that might get within 120W peak usage: 1. Use laptop components, ie ultra low usage CPU and memory + reduced capability motherbiard and a couple of 4200 rpm hard drives. 2. Use an embedded chip such as the VIA C7 which you should be able to get with a max power draw of around 20 W, combined with their motherboard and 2GB of RAM you should again be able to spec something below. Either way you are not going to be looking at a server class machine, for a reasonable server you are realistically looking at needing 1.5 - 2.0 Amps per machine, which will get you a dual core, 4GB of RAM and 2 x hard drives basic setup. If possible find another colo - because it sounds like they have serious power problems. ---
**Author:** ![softf5ajivanet](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/s/9f8e36/32.png) [@softf5ajivanet](https://www.ruby-forum.com/u/softf5ajivanet)\ **Post date:** [March 3, 2008, 10:40pm UTC](https://www.ruby-forum.com/t/building-1u-rails-server-power-calculations/130655/11 "2008-03-03T22:40:22Z")
Well I spoke to some experts and they believe that the theory and practice are totally different. A dell 860 server default spec will pull about 0.6A, despite being rated at 345 Watts on the PSU. So its average usage is far lower than you would expect based on the peak figures. What I also learnt however is that every 0.1 A costs you about £4, so if you max out your server day and night then you could be looking at £60 extra in power bills on top of your £34 hosting, ouch! Good luck with your colo, personally based on what I’ve seen I’d be tempted to go managed unless it really matters, as colocation is looking like a really expensive option. Do a comparison for instance to Amazon’s EC2 and its night and day in price. I hope that helps. ---
**Author:** ![softf5ajivanet](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/s/9f8e36/32.png) [@softf5ajivanet](https://www.ruby-forum.com/u/softf5ajivanet)\ **Post date:** [March 3, 2008, 9:48pm UTC](https://www.ruby-forum.com/t/building-1u-rails-server-power-calculations/130655/12 "2008-03-03T21:48:17Z")
I have looked further into this and it does appear that many of the UKs top colocators have similar deals with only 0.5A per 1U. Its a ridiculously low amount of power for any modern server, because I can’t find a single one (despite how slow you go) that gets remotely that low. About the best I can find is a 1Ghz Pentium 3 with 512MB of RAM on Scan (£350!) that manages to go as low as 240watts. That is still double the power usage your targeting and its a zillion years old. I do remember when I was last putting in boxes into a rack at Telecity (Docklands London) that we couldn’t fill every slot because of power constraints, and I think we got a maximum of 32Amps for 32U cabinet there. That is double what most colocators are offering and still half of what realistically is needed. I know a lot of data centres don’t like blades as the power density is high and from IBM you can get 14 blades (that’s upto 28 CPUs, 56 cores with an E series) in 7U. The power usage as far as I can tell is a modest 2000 W (8.3 Amps). That is just under 1.2 Amps per blade, which is closer than most of the 1U servers but still far in excess of fitting into 0.5A. There is something I’m missing here because whatever way I look at it I can’t see 0.5A being remotely doable. I’ve asked some questions of some colleges who do this sort of thing more often, will get back to you in a day or so. ---
**Author:** ![softf5ajivanet](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/s/9f8e36/32.png) [@softf5ajivanet](https://www.ruby-forum.com/u/softf5ajivanet)\ **Post date:** [March 4, 2008, 12:00am UTC](https://www.ruby-forum.com/t/building-1u-rails-server-power-calculations/130655/13 "2008-03-04T00:00:30Z")
Thanks Paul for looking into this, seriously appreciate the time and effort you’re putting in really. Yep, I had a playaround with Amazon EC2 and found that the service was good but it proved to be slow in data transfer, was cheap mind. I’ve sourced parts this weekend and today and still see this as a doable thing, a friend of mine is doing the same and has managed to put together a pretty decent AMD 2.4ghz x64 dual core while still keeping under the limit, hence my attempt. However it’s more-so out of experience and wanting to try something new, I’ve never done this and have always viewed it as a grey area in my experience; i’ve built everything else and run several managed servers but never tried to build my own. I’ll let you know how it turns out, waiting on parts to arrive before I buy the main hardware so it’ll be another month till I really go into this. Also thankyou Robby, I want to use XEN to split up the box and will probably go this route as it adds to the experience gained and your layout certainly sounds like the way to go; much appreciated. All the best and thanks for your effort Paul, Robby, Anibal and Ben, appreciated! John. ---
**Author:** ![softf5ajivanet](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/s/9f8e36/32.png) [@softf5ajivanet](https://www.ruby-forum.com/u/softf5ajivanet)\ **Post date:** [March 4, 2008, 6:44pm UTC](https://www.ruby-forum.com/t/building-1u-rails-server-power-calculations/130655/14 "2008-03-04T18:44:15Z")
You could try a Sun T1000, 6core 1Ghz, 4 x 1Gb ram, 1 x 3.5" sata SUN power calculator claims 136watts idle 177watts max OR Sun T5120 (which appears to be over your requirement) 4core 1.2Ghz, 4 x 1Gb ram 2 x 2.5" 73Gb SAS SUN power calculator claims 159watts idle 232watts max Aaron ----- Original Message ----- From: “Paul K.” [removed\_email\_address@domain.invalid](mailto:removed_email_address@domain.invalid) To: removed\_email\_address@domain.invalid Sent: Tuesday, March 4, 2008 7:48:17 AM (GMT+1000) Australia/Sydney Subject: [Rails-deploy] Re: Building 1U Rails Server - Power Calculations? I have looked further into this and it does appear that many of the UKs top colocators have similar deals with only 0.5A per 1U. Its a ridiculously low amount of power for any modern server, because I can’t find a single one (despite how slow you go) that gets remotely that low. About the best I can find is a 1Ghz Pentium 3 with 512MB of RAM on Scan (£350!) that manages to go as low as 240watts. That is still double the power usage your targeting and its a zillion years old. I do remember when I was last putting in boxes into a rack at Telecity (Docklands London) that we couldn’t fill every slot because of power constraints, and I think we got a maximum of 32Amps for 32U cabinet there. That is double what most colocators are offering and still half of what realistically is needed. I know a lot of data centres don’t like blades as the power density is high and from IBM you can get 14 blades (that’s upto 28 CPUs, 56 cores with an E series) in 7U. The power usage as far as I can tell is a modest 2000 W (8.3 Amps). That is just under 1.2 Amps per blade, which is closer than most of the 1U servers but still far in excess of fitting into 0.5A. ## There is something I’m missing here because whatever way I look at it I can’t see 0.5A being remotely doable. I’ve asked some questions of some colleges who do this sort of thing more often, will get back to you in a day or so. Posted via [http://www.ruby-forum.com/](http://www.ruby-forum.com/). ---
**Author:** ![softf5ajivanet](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/s/9f8e36/32.png) [@softf5ajivanet](https://www.ruby-forum.com/u/softf5ajivanet)\ **Post date:** [September 29, 2008, 12:38pm UTC](https://www.ruby-forum.com/t/building-1u-rails-server-power-calculations/130655/15 "2008-09-29T12:38:23Z")
built it in the end, was a little traumatic but running fine now on 0.4A in colocation. ASUS M2A-VM VGA board WESTERN DIGITAL 1TB green drives x2 CORSAIR XMS2 DDR2 2GB PC2-6400 x2 Dynatron A48G fan (hardest to obtain, get it from ebay) SuperMicro 1U case (turned off two of the fans so only two blast against the drives o/s : debian etch on the bios remember to turn off things you’ll never use (printer port, serial port, etc.) to conserve even more power debians very stable, if you need anything newer just hook it up to the backports repository. here’s the commands i ran to deal with the o/s > **[WordPress.com](https://wordpress.com/typo/?subdomain=red91)** > > WordPress.com is the best place for your personal blog or business site. …i’ll pretty up that later, hope this helps, let me know if anyone needs any more help on this, John.