James Kirk wrote: > I would like to install debian on a SD (I've only a Company laptop > and I would like to not modify the standard configuration). Sounds reasonable to me. > Since SD is a flash memory and - as far as I know - it has a limited > lifetime (in terms of I/O) not thought to run an OS, The quality of the SD depends upon the vendor. And unfortunately it is a "market for lemons" in that it is difficult for consumers to know which are better than others. But AFAIK most SD cards do implement at least some internal spares and wear leveling. > how should I > setup the installation (i.e. choosing a suitable filesystem, etc.) > and/or modify the standard distribution in order to have a > fully-functional Debian and make it compatible with a SD lifetime? You might look at Raspberry Pis, BeagleBone Blacks, Cubieboards, and many other systems routinely run from SD cards. Read the install docs and blogs for those types of systems and see what tweaks they suggest. They have been running on SD cards for quite a while now. Personally I don't do a lot of tweaking. I have been running an RPI system off of an SD since January 2013 24x7 plus several others for the last six months 24x7 and haven't had any problems with them yet. I normally set up a tmpfs in /etc/default/tmpfs. I don't do anything special with /var/log although I know some people put it on a tmpfs too but I like to see the logs if there is a reboot. I do use the noatime flag in /etc/fstab. I keep a backup. Which because it is an SD card is very easy to make a full device snapshot every so often. Talking about tuning the Raspbery Pi folks set vm.swappiness=1 which I disagree with. I suggest using the Linux upstream default of vm.swappiness=60 or even higher. Proponents of disabling program swap by setting it low say that they never want to swap. I have the opposite viewpoint. The point is to use the existing ram most effectively. If that means using ram for file system buffer cache instead of parts of programs that aren't ever accessed again then swapping out unused program space is better than hogging ram with it. Bob
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