Re: [gentoo-user] Tips for saving power needed...

[Michael Mol <mikemol@gmail.com>]

On Mon, Apr 2, 2012 at 7:57 AM, Pandu Poluan <pandu@poluan.info> wrote:
>
> On Apr 2, 2012 5:00 PM, "Robert David" <robert.david.public@gmail.com>
> wrote:
>>
>> Hi,
>>
>> maybe write your hw configuration first. Eg: CPUs, graphic cards, HDDs
>> (size, speed, type) and others.
>>
>> Also provide lspci output and /proc/cpuinfo.
>>
>> Then this is a server, maybe with more than one GB nic. If you dont use
>> spare nics disable them in bios. Do the same with other unneeded stuff.
>>
>> If you can access your server and replace cards, remove everything you
>> dont need. Do not lower fans or dont play with cpu voltage. If you want
>> to run this server 24/7 it can cause serious problems. It will not save
>> you much power. Paradoxly this could lead to higher power usage in
>> some cases, because of hotter devices.
>>
>> Remove spare memory cards, if you dont need much memory, etc.
>>
>> Robert.
>>
>> V Sun, 01 Apr 2012 17:04:58 +0200
>> Jarry <mr.jarry@gmail.com> napsáno:
>>
>> > Hi,
>> >
>> > admin of a colo-center keeps complaining my server is going
>> > a little over power-limit (which they have set as ~120W per
>> > 24h/avg, while my server needs ~130-135W). So I need to find
>> > a way to save at least those 15W, or I will be moved to
>> > higher tarif (which means higher costs for server-housing).
>> >
>> > Before going hard(ware) way, I would like to try first
>> > all possible software solutions. What I tried up to now is
>> > cpufreqd, CONFIG_NO_HZ=y, and spindown. In addition to that
>> > I adjusted fan-speeds to a little lower values and turned
>> > off some unneeded peripherials (in bios).
>> >
>> > Is there anything else I could do? Any tips would be greatly
>> > welcomed...
>> >
>> > Jarry
>> >
>>
>>
>
> I'd rather have *more* RAM than causing unnecessary swaps.
>
> Try using a smaller swapfile to reduce swap tendencies. You can always push
> a larger swapfile into service when needed.
>
> There's also a kernel knob to set 'swappiness', but I forget what exactly.
> Try 'sysctl -a | grep swap'

Swappiness is the knob you want to set if you want to reduce
swappiness. I set mine to 0; swap only when absolutely necessary.

In /etc/sysctl.conf:
vm.swappiness = 0

On the command line:
sysctl -w vm.swappiness=0

-- 
:wq