How to Install Clean Without Trashing /home or other usable data

[Michael A. Peters]

On Fri, 2005-10-28 at 12:55 -0400, Temlakos wrote:
> In the "Why Fedora?" thread, Michael A. Peters wrote:

>  >
>  > Yes - that's what I do.
>  > Not NFS, though - just a separate /home partition.
>  > I back up my ssl certs etc. - then do a clean install but don't
>  > format /home
>  >
> 
> That's it? Just don't format /home, but format all other partitions? 
> (Could I perhaps get away without formatting /var/lib, if I break that 
> off as separate? I keep databases and home-built yum repos there.)

I use a partition mounted at /var2 for some of that stuff (IE my ftp and
web server are in there, I just change the config files to look in /var2
instead of /var) - the one exception being my caching nameserver, its
data sits in /var - I probably should look into changing that.

That way if one of my rsync maintained yum repos grows too big, I don't
run out of room on / and the /var itself is still available for stuff
the OS needs in /var that isn't specific to me.

I do make a tarball of /etc before I do a clean install so that I can
look at my customized config files and compare them with the clean dist
installed config files.

> 
> Can I manage that if I use Logical Volume Management?

Yes. I use LVM for / /home /data and /var2 (/data is where I have things
like bittorrent put their stuff, and my flac collection - it's its own
hard drive). With LVM you can grow those partitions as necessary - but
if/when they do run out, / still has plenty of room so that the OS is
still usable.

> 
> And once I do that: do I then have to re-establish all user accounts in 
> the order in which I created them to begin with?
> 

Usually I diff my old passwd and group files against the newly
installed. If the newly installed hasn't changed or added any UID/GID's
- then I just replace the new /etc/{passwd,shadow,group} files with the
old ones. If they have changed, then I use groupadd and useradd with the
appropriate switches to add the users and groups I want, and reset the
passwords.

NIS would be a better solution for me probably, but I haven't looked
into that yet.

Since your non system UID/GID's will all be 500 and above, you could
just make backups of your existing /etc/{passwd,group,shadow} files,
delete all entries below 500, and then after clean install - cat them
onto the newly created ones (using >> ).

Perhaps I should write a script that automates that - it wouldn't be
hard. That would preserve UID/GID and passwords.