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Many FreeBSD users tell me that FreeBSD has the smallest footprint in terms of CPU & RAM usage.

I'm looking for a server OS with the smallest possible CPU & RAM usage, so I will try FreeBSD in my server.

This may create more problems, since not too many people are using this OS.

Do you have suggestion?

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closed as not constructive by MDMarra, Iain Jul 7 '12 at 20:32

As it currently stands, this question is not a good fit for our Q&A format. We expect answers to be supported by facts, references, or expertise, but this question will likely solicit debate, arguments, polling, or extended discussion. If you feel that this question can be improved and possibly reopened, visit the help center for guidance.If this question can be reworded to fit the rules in the help center, please edit the question.

FreeBSD has a pretty decent userbase of very knowledgeable people. I wouldn't worry about that too much. Bigger issue would be your personal experience and knowledge on the matter.

Ask yourself (and tell us): why is it so important to have a couple of megs of extra free RAM in your server? What does that gain you? And what does it cost you, both in terms of money and other performance factors? Are you on a VPS and do you have to pay for CPU cycles? Will FreeBSD support your hardware? Does FreeBSD provide the same IO throughput on your specific server? Does your application support FreeBSD?

I'm assuming those last points are an issue, as you are clearly looking for something that can provide a lean & mean platform for some application.

Anyway, I got a bit curious myself, so I started a couple of KVM virtual machines on my laptop. I'm currently into Django development, so I this is what both of them are running: Django (manage runserver, nothing fancy on the FreeBSD box, a development project on a Fedora 12 box), PostgreSQL 8 and Cherokee, just so to have something running.

The Fedora box I have used for a couple of weeks to do development on, the FreeBSD box I have installed a few days ago to polish my FreeBSD skills, which largely have been dormant over the past couple of years. I have installed very few ports on the FreeBSD box.

The Fedora box now shows 22M in buffers, 80M in cache and 100M in use out of 512M. Basically, that leaves around 400M of free RAM.

The FreeBSD box now shows almost no cache, 60M in buffers, 33M of active RAM, 27M of inactive RAM and 68M 'wired'. The FreeBSD 'top' utility shows a total of 355M RAM free out of the same 512M.

Now, first of all, I'm a Linux guy, so I'm not one to explain in detail the meaning of the various memory states on FreeBSD. You can read a bit about it here though. Second of all, of course this is not a serious test. It's just to provide an indication. What is does show, however, is that no matter how you put it, the differences between the two operating systems is going to be small, either way.

So, to make a long story short, don't stare yourself blind on stuff like this. Go with the *nix that you're most comfortable with or the one you are willing to invest some time in.

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I get the feeling that you're wanting a *NIX like operating system, however, if you're asking this as an academic pursuit - one of the most featureful, bang-per-k-of-RAM OS' is Contiki Contiki Website,which can run in as little as 2k of RAM.

If you're looking for a small *NIX-like system, certain versions of Puppy-LinuxPuppy Linux Website can boot with 32MB of RAM.

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+1 for mentioning Contiki, the unbelievably small OS :) – wzzrd Dec 31 '09 at 14:08

If you aim run it in a virtualized environment there are the JEOS (Just Enough Operating System) versions of Ubuntu to consider. Basically they have had a lot of things that are unnecessary stripped out:

Ubuntu JEOS

Suse seems to have one as well:


The BSD's have their own micro distributions as well:


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Having stuff stripped out doesn't necessarily mean having a low memory and CPU footprint. JEOS platforms are meant for appliances for which it is important to lower the installed software footprint because that lowers maintenance overhead. Memory and CPU usage will not lower if you leave out vim-enhanced or the manual pages. – wzzrd Dec 31 '09 at 14:00
They are not just stripping out the man pages. From the Ubuntu JEOS page: JeOS is a specialised installation of Ubuntu Server Edition with a tuned kernel that only contains the base elements needed to run within a virtualized environment. – davey Dec 31 '09 at 16:25