Saving Space mini-HOWTO
v1.0.1, 7 April 1999
This mini-HOWTO gives you directions for squeezing your Linux installation
into the least possible space. It's particularly aimed at notebook users.
I've got a notebook I installed Linux on, beside Windows 95 that was
pre--installed. I squeezed the Windows partition to 500 Mb, making space for
a 240 Mb Linux one. Small though the latter may seem, I've managed to
install a fairly complete Linux system on it, based on Red Hat 4.1 and some
magic to save as much space as possible.
If you're in need for space, the indications you'll find in the following
sections will free up a considerable chunk of hard disk. The only caveat I'm
giving you is: don't blame me if something goes wrong! We'll be using a
couple of programs that worked fine for me, but are inherently dangerous.
You've been warned.
You need:
There are other executable compressors. One is gzexe (forget it), while
tcx was probably the best before upx became available; yet another
is tzx, in theory better than tcx. The thing is, it screwed
everything up when I tried it on a spare PC, though I'm not sure if I did
something wrong. You had better stick with upx: it's reliable,
efficient, and very handy.
There are kernel patches that provide transparent file system compression a
la Stacker, but as of this writing none of them has yet a reputation for
stability and reliability. For safety's sake, steer clear.
The kernel sources take up more than 20 Mb, and you may want to remove them.
If so, I suggest that you compile a new kernel that is tailored to your
machine once and for all, then get rid of the sources. Take care, though.
I don't recommend that you remove the kernel sources unless you are
sure that your machine is properly configured. Besides, you need the kernel
#includes to compile C programs. Think twice!
If you do decide so, do not remove the include/linux tree
unless you know you'll never compile applications on your machine.
Now, decide which applications you really need. Some may prove
redundant: for instance, are you sure you can't live without emacs? You
could use jed instead.
It's up to you to decide what you want to keep. Some general points:
-
gcc is a fairly large package. It's needed to recompile the
kernel and all the applications for which there are no pre--built Linux
binaries. It's also needed, of course, if you write your own C or Fortran
(with f2c or g77) programs; consider your needs before removing it.
Other compilers like lcc are fine, but not up to gcc level. I
suggest that you keep it;
- X11 is awfully large, but it's a nice thing to have. If you decide
you can't give it up, at least try to make do with as little as necessary:
only the right X server, one simple window manager, only one
xterm, no 100 dpi fonts, and so on;
- TeX and accompanying packages are very large indeed. Giving up LaTeX
and sticking to plain TeX saves a lot of space; giving up X11 previewers
like
xdvi and ghostview is possible if you use dvitty,
dvivga and some such. Eliminating the need for X11 dviware could even
make X11 redundant;
- games are never ``necessary''.
Let's start reducing the size of binaries. Move to /usr/bin and
issue the command
machine:/usr/bin# strip *
which will do away with symbols embedded in binaries. Repeat this
step in /usr/X11R6/bin/ and other directories containing
executables you may have (don't forget to locate TeX's and gcc's
binaries), but do not run it under /sbin,
/bin, or /usr/sbin/ if you value your installation!
First, install upx and read its documentation. Then go to
/usr/bin and run it with the command upx *; it will
compress all executables, including suid ones (tcx wouldn't). Repeat
this step in other directories as seen above.
Remember to compress the executables whenever you install a new package!
There are lots of other files that can be compressed once and for all. Let's
start with /usr/doc/; move to this directory and issue the
command
machine:/usr/doc# find . -type f -exec gzip -9 {} \; 2> /dev/null
Remember to compress the docs whenever you install a new package!
Repeat this step in the directory containing the documentation for TeX (on
my system, /usr/lib/texmf/texmf/doc/. If you're
really sure, remove these directories altogether.
Now, install zlibc and compile it. If your system is like mine, the
compilation process will abort complaining about a missing (static) libc.
Never mind; you'll find a file called uncompress.o that is what's
needed. Move it to /usr/local/lib/ and add this line to your
/etc/profile:
export LD_ELF_PRELOAD=/usr/local/lib/uncompress.o
Now, you can compress with gzip not only documentation, but also data
files: the applications that use them will be able to use them nonetheless.
In theory, the trick should work with most applications, but in practice
your degree of success may vary. Mine was rather unimpressive.
This is what I got applying the above procedure to one of my machines.
Before the treatment, df reported I used 398,798 1024--blocks:
- I didn't remove the kernel sources and the kernel headers;
- I uninstalled several applications and all of the games, but I left
X11, X11 development, C and Fortran development, Tcl/Tk, networking tools,
and a few other standard applications.
df reported 244,668 used blocks;
- I ran
upx on /usr/bin,
/usr/X11R6/bin, /usr/lib/texmf/bin/i586-linux,
and /usr/lib/gcc-lib/i386-linux/2.7.2.1. 226,270 used blocks;
- I compressed the documentation under /usr/doc and
/usr/lib/texmf/texmf/doc: 198,745 used blocks.
To sum up, I started with 398,798 blocks and finished with 198,745. Think of
the stuff you can shove in those 200,000 spared blocks! I would have saved
even more if I had used bzip2 instead of gzip.
On average, if you are careful from the beginning and install only the
necessary applications, compressing executables and documents will save you
some 20 Mb. On a notebook, this can be a lifesaver.
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``Saving Space mini-HOWTO''was written by Guido Gonzato,
REMOVE_MEguido@ibogeo.df.unibo.it.
This document is provided ``as is''. I put great effort into writing it as
accurately as I could, but you use the information contained in it at your
own risk. In no event shall I be liable for any damages resulting from the
use of this work.
Feedback is welcome. For any requests, suggestions, flames, etc., feel free
to contact me.
Enjoy Linux and life,
Guido =8-)
