Hi,

I am planning to re-use an old laptop in the basement storage to power an external USB-harddisk for backup purposes. This doesn't require a lot of CPU power, and since the box will be put in a closet, I want it to consume as little power as possible in order to emit as little heat as possible.

So far on my wish-list I'll use ACPI power-settings to tune the CPU to the lowest possible frequency and avoid pretty much anything loaded besides NFS, SSH and a firewall.

I would greatly appreciate any suggestions for kernel compile options and other things to tweak in order to make this laptop as cold as possible!

Thanks in advance,

-y1

Enable the powersave cpu frequency scaling governor in the kernel configuration (CONFIG_CPU_FREQ_GOV_POWERSAVE):

Power management and ACPI-> CPU Frequency scaling -> powersave

Thanks tramni1980! However, the scaling governors only change the CPU frequency, so by locking it on the lowest speed I believe to achieve more than running the powersave governor.

Are there any other interrupt or IO/related settings that could help reduce power consuptions?

http://www.lesswatts.org/projects/powertop/

And turn hal off, or at least explicitly disable device polling.

Hi,
Why the firewall? Will the machine be exposed to the internet or just your LAN? If your LAN then look at setting up a 'DMZ'. Minimize all services. You should TP Ethernet instead of wireless. Disable in the BIOS the display & VGA, disable any of the configurable sub-systems, video, wireless or whatever your not going to use. Most older laptops allowed this ability of disabling un-wanted devices.

You should look at your storage media configurations via 'hdparm -I /dev/Your_device'. Then adjust as you need.

Trim the kernel to suit the install hardware to be used. I would start with a 'Minimal System' install then work from there.

Looking at this page it seems that setting NO_HZ in the kernel config leads to significant power saving.

Before I find out the hard way, can anyone confirm this in slackware 13 and advise of any potential drawbacks in setting NO_HZ? (Must be a reason why PV didn't set it.)

I must say that I disagree and that I disagree with the Minimal System install in general. Let me explain...

When choosing to install anything less than everything you are choosing to sacrifice future flexibility and available options for system resources. This can be a necessary sacrifice. When hard disk space is limited, it is especially necessary. Further, In RedHat-based systems (for example) when you install something that has a daemon component, that daemon is started by default and so purely by installing the software you are impacting on boot-time, available RAM and processing cycles unless you choose to customise or disable it.

In Slackware, the issue is not the same. Even in Full installation mode there is a small set of services that are started by default, and during installation you are prompted to modify this small set to meet your needs. If you wish to have more services start then it is up to you to enable them for boot-time and start them. This means that the inclusion of all of the available software does not necessarily have any impact on available resources other than hard disk space.

To this end, I only ever recommend that someone install anything less than the Full set of packages if they have very limited disk space (or for some reason extremely poor-performance storage); but in the past decade storage space has become so cheap and compact that space has almost exclusively become the concern of people storing large amounts of media. The 4 or so gigabytes needed to install all of Slackware is usually negligible.

To sum up:
If HDD space is a problem, Minimal Install is a good starting point.
In all other cases, you do yourself a favour by using the Full install.

zordrak:
This is, of course, correct; & I also tend to do a full install for a desktop system, then, later, go into "pkgtool" & take out what I don't want/need. But Y1 specified a backup server application. That is an entirely different plate of worms. If I'm installing a server, I start with a minimal system & add some to it, rather than start with everything & just begin the paring down by taking out all of X, then any X-related programs.
Regards,
Bill

You're still talking about removing packages. If hard disk space is not a consideration there is just no need. Leave X in and so long as you usually run it in runlevel3, it's as if it isn't there.. until the day you want to compile against an X library, or you want to start fluxbox for 30 seconds to play around with something, and then shut it down again. The same goes for all the rest of the packages. You can even completely re-assign the server to a completely new task just by changing the configuration, not having to install/uninstall a ton of packages.

Not to mention that, and I will say this again: so long as disk space is not a concern, you save all that time you'd waste choosing individual packages to add/remove and then doing it.

1 members found this post helpful.

zordrak:
No, I'm not. I have several sets of tagfiles (thanks to AlienBob's tagfile generator script) that allow me to do different installs based on what I want to do with the partition. But, with disk space costing what it does today, I do agree that for the average/new user, or for that user that just doesn't want to "prank" with his system (my wife would say that I "prank" our systems all the way down to parade rest!), doing a full install & using the stock kernels is the best method.
Regards,
Bill

If you are looking to conserve power, why not use something like wake-on-lan if the laptop supports it. Then, if you have a script to do your backups, just have the script wake the machine and sleep for x amount of seconds then do the backup. I would also have another script on the laptop to put it back to sleep after x amount of time.

You argue your case well and I agree with much of it ... but, while HDD space is seldom a constraint now, backup space is -- especially if multiple copies of full backups are chosen for ease of recovery (possibly to a state some time ago) and for backup media redundancy. This issue is compounded in my situation because DVDs are the least bad media choice being in the tropics without AC.

Obviously everyone's situation is different and I'm talking about the majority of generic setups.

With respect to backing-up, often all that is truly required is the contents of /etc, /var/log/packages and perhaps /srv & /var.. most of the space taken by a full install is in /usr which doesn't necessarily require a backup so long as you have the install media.

Incremental backups and/or snapshot backups also reduce backup space required to just that which has changed. Personally I'm in the lucky position of having 32 tapes in a robotic library with a maximum theoretical storage capacity of over 25TB.

Of course none of this covers DVD backups That's where being a good SysAdmin who knows the best way to deal with his/her own situation comes in; and is what pays your salary

If drive space is a concern (and even if not), consider using rsnapshot. I use rsnapshot for my backup strategy. I am able to keep backups for many months because rsnapshot uses rsync and hard sym links to minimize storage space consumed. Quite nice.

+1 for rsnapshot