Re: Reducing root filesystem

Padraig Brady
2002-04-10T19:10:09Z

Amol Kumar Lad wrote:
> Hi,
> I am porting Linux to an embedded system. Currently my rootfilesystem is
> around 2.5 MB (after keeping it to minimal and adding tools like busybox). I
> want to furthur reduce it to say maximum of 1.5 MB.
> Please suggest some link/references where I can find the details to optimise
> my root filesystem
>
> thanks
> Amol
>
> please CC me

Obviously it depends what logic you want in your root partition,
but without too much effort we've created the following minimal
system that can do web downloads and write flash cards, and is
generally very configurable with shell scripting etc.
Note we used dietlibc for our binary. Note also when we did
this buysbox was not compatible with dietlibc.

5 /boot/message
10 /etc/hosts.allow
12 /etc/host.conf
24 /lib/modules/2.4.16-9afo/modules.pnpbiosmap
29 /lib/modules/2.4.16-9afo/modules.parportmap
31 /lib/modules/2.4.16-9afo/modules.generic_string
51 /bin/runlcdd
73 /lib/modules/2.4.16-9afo/modules.ieee1394map
81 /lib/modules/2.4.16-9afo/modules.isapnpmap
81 /etc/sysconfig/network-scripts/ifcfg-eth1
99 /lib/modules/2.4.16-9afo/modules.pcimap
101 /etc/fstab
103 /etc/passwd
108 /etc/group
120 /etc/issue
125 /etc/sysconfig/network-scripts/ifcfg-lo
127 /etc/hosts
134 /etc/shells
189 /lib/modules/2.4.16-9afo/modules.usbmap
192 /etc/suauth
238 /etc/nsswitch.conf
281 /bin/rescue.ash
396 /etc/inittab
538 /etc/profile
595 /etc/protocols
976 /etc/init.d/rc
6008 /boot/boot-text.b
16406 /bin/afrescue
20480 /boot/map
102273 /lib/modules/e100.o
674931 /boot/bzImage
717992 /bin/busybox
--------
1542809
========

So to get this even smaller:

1. Get busybox working with dietlibc/uclibc (this probably already done)
2. use something like UPX to "transparently" compress executables.
3. use e2compr to transparently compress the whole filesystem
(gzip/bzip2 available). dri@sxb.bsf.alcatel.fr has a patch for this.

Padraig.