Coda File System

Re: coda on linux

From: Andreas Jellinghaus <>
Date: Mon, 23 Mar 1998 11:37:23 +0100
>  I've been running coda on Debian for some time now, and also created a
> set of debian packages (coda-client, coda-server, coda-backup,
> coda-doc). However, they do not have any postinstall-configuration.

great ! configuration is not so important, we can write a howto :-)
i saw man pages in the postscript docs. are these manpages also in the
sources (i ask, because i didn't see any)..

my idea how to use coda is :
i have a linux server, and 80 pc's booting win* or linux.
currently they boot win95, loadlin, linux, get the rootfs via nfs
(readonly, it's / of the server), mount /var from the server (rw)).

my problems are :
 - 80 machines, working 100% via nfs, but the infrastrcuture is only 10
	mbit, some parts not even switched.
 - i could use a few 100 mb of hard disk space, but that doesn't help
	much (server installation has 2-3 gb of software), and will make
	administration much harder.
 - every linux machien can be hacked evry easily : use win* to download
	a linux installation/rescue disk, and boto this disk. mount
	remote filesystems via nfs. the real root is readonly, so except
	reading secrets, the user can't do much. but homedirectories
	have to be read-write, so they are vulnerable.

coda could help (if i understodd everything right) :
 - useing several 100 mb as cache will reduce network load a lot.
   after a reboot, coda can use the data again and will detect changes.
 - i still can mount the root from nfs, but then load the rest from
   coda, useing venus/cache. either i will move /opt and /usr to coda,
   or chroot to /coda
 - not even root on a poolpc can access the homedirectories, unless he
   knows the password.

problems i see so far :
 - is coda stable enough
 - ticket expiry of 25h. for calculations lomger than 25h this could eb
	a problem.
 - after login via xdm, the home direcotirs are still protected. so i
	need to call some application in the global Xsession file, that
 	will ask for a password and clog.
 - coda servers don't hold data on normal filesystems, so during test
   phase, i need all data twice - once on ext2 for nfs export, and once on
   coda partitions
 - currently i export / but block several subdirs with "noaccess", and
	mount /var from "/export/`hostname`/, becuase every server needs
	its  own /var/tmp (/tmp is a symlink to /var/tmp), /var/log ...

how do other people administrate unix machines ?
the simplest solution, is to have a seperate installation on every
machine, and share only some parts via nfs or coda. many people use
nfsroot, so they have a central administration. but nfsroot requires a
fast network, and everything depends on the state of the nfs server.

how fast is coda (venus cache hits) ? i hope it will not be as fast
as direkt hard disk useage, but much faster than nfs.

with hoard a client machine will continue to work, if the server is down
for a few minutes.

so, what's left ?
 - i can't mount / as coda filesystem
 - i need a few config files in each pc's /etc to differ 
	(inittab, XF86Config and Xserver)
 - i need a per host /var tree, at least tmp, log, run, spool,
	but share "lib"

but finding a way to have _one_ linux installation for a large group of
machines, would rock. suggestions ?

> My lastest packages are build from coda-4.3.13, but I should get it up
> to 4.4.0 this week. I can then send you my .dsc/.diff.gz files, if you'd
> like.
> (About some of your compilation problems:
>  - You need to start the compilation using `make coda'
ah. i knew there was something. maybe "coda" should be the default target ?

>  - It's also better to compile the kernel module using the code included
>    with the 2.1 kernels, or from the linux-coda-4.4.0.tgz package).

yes, i'm running 2.1.90 with linux-coda 4.4.0 module.

Received on 1998-03-23 05:40:36