On Sun, 2008-01-06 at 00:36 +0000, Ed W wrote:
> > I do something very similar in my alpine linux distro. Instead of just
> > continuing in initramfs, the init script mounts a tmpfs, finds a base
> > installation (2-3MB) and "switch_root" to the tmpfs. From here it loads
> > a set of packages (from usb/cdrom/cf) and configuration (from
> > usb/floppy/cf).
> > >From this base installation it is possible to mount disks, raid, iscsi,
> > lvm and fire up vserver guests.
> Hi Natanael
> I have followed your posts in gentoo-embedded mailing list. I have only
> examined alpine-linux a little, but I'm not quite sure why you use the
> tmpfs rather than say keeping with the initramfs and perhaps using aufs
> to overwrite with additional packages, and perhaps even adding a
> writeable /etc directory? (Actually on the wrt linksys distros they
> often add a writable partition with symlinks into /etc, or vice-versa)
Several reasons. Mounting a second tmpfs (rather than using the given
initramfs) gives the user the possibility to manually set the size of
the root fs.
Since everything runs from tmpfs (with kernel modules as exception) you
are able to eject the cdrom/usb once system is booted.
Historically it was possible to boot alpine from floppy.
> Having only an initramfs seems like a very sensible solution for
> Michael? He could use a second partition for writable stuff and mount
> it rw - then simply symlink in anything required from the static
> partition to give a kind of updatable /etc/ (or whatever)
Might be I will gor for initramfs only too, now that recent kernels
don't fit on a floppy anyway.
> I'm researching something similar myself, but in my case I want quite a
> lot of stuff in the base distro (30-60MB perhaps) and so your tmpfs
> approach seems like quite a waste when I only have 128 or 256MB or ram
> on the devices I want to use...?
Things that are in use (running daemons) will be in RAM anyway and if
you have a swap, the memory manager will kick out unused stuff from RAM.
But sure, if tmpfs only is a good approach or not depends on your goals.
> Anyone else got any other thoughts on this?
> Ed W
Received on Mon Jan 7 08:29:58 2008