Re: How can i migrate from Mandrake 7.2 to RedHat 7.2

>>>>> "John" == John Loukeris <[email protected]> writes:

John> Hello, Our company's file server has Mandrake 7.2 installed.  Can i
John> switch to Red Hat 7.2 without loosing my data ? 

Assuming the data you're speaking of is in a partition that is separate
from the normal system-level directories, you should be able to do a fresh
install of Red Hat Linux, instructing the installer to mount your data
partition in the proper place, but to *not* format it.  I do this all the
time with the partition that contains my home directory -- I do a fresh
install, but direct the installer to mount that partition on /home, and to
not format it.

John> There is a soft raid installation on this machine with two SCSI
John> drives in raid1 (mirror) mounted on /var. 

Ah, I guess I should've read ahead a bit before writing all that other
stuff... :-)

Putting user data in /var is somewhat strange; unfortunately, here's a
directory listing of /var on my Red Hat Linux 7.3 system:

[root@raptor ed]# ls -al /var
total 108
drwxr-xr-x   27 root     root         4096 May  4 19:00 .
drwxr-xr-x   22 root     root         4096 May  9 20:01 ..
drwxr-xr-x    2 root     root         4096 May  4 19:00 account
drwxr-xr-x    2 pcap     pcap         4096 May  4 18:44 arpwatch
drwxr-xr-x    7 root     root         4096 May  4 18:42 cache
drwxr-xr-x    5 netdump  netdump      4096 May  4 18:59 crash
drwxr-xr-x    2 root     root         4096 May  4 18:59 db
drwxr-xr-x    6 root     root         4096 May  4 18:42 ftp
drwxr-x---    2 gdm      gdm          4096 May  9 20:02 gdm
drwx------    2 root     root         4096 Feb 22 08:02 iptraf
drwxr-xr-x    3 root     root         4096 May  4 18:56 kerberos
drwxr-xr-x   25 root     root         4096 May  4 19:55 lib
drwxr-xr-x    2 root     root         4096 Feb  6  1996 local
drwxrwxr-x    5 root     lock         4096 May 10 04:02 lock
drwxr-xr-x   16 root     root         4096 May  9 20:01 log
lrwxrwxrwx    1 root     root           10 May  4 17:21 mail -> spool/mail
drwxr-xr-x   15 root     root         4096 May  4 18:58 mailman
drwxr-xr-x    4 root     root         4096 May  4 18:58 mars_nwe
drwxr-xr-x    2 named    named        4096 May  4 18:43 named
drwxr-xr-x    2 root     root         4096 Feb  6  1996 nis
drwxr-xr-x    2 root     root         4096 Apr 13  2000 opt
drwxr-xr-x    2 root     root         4096 Feb  6  1996 preserve
drwxr-xr-x   11 root     root         4096 May  9 21:01 run
drwxr-xr-x   22 root     root         4096 May  4 19:03 spool
drwxrwxrwt    2 root     root         4096 May 10 07:13 tmp
drwx------    2 root     root         4096 Mar 27 17:51 tux
drwxr-xr-x    6 root     root         4096 May  4 18:59 www
drwxr-xr-x    3 root     root         4096 May  4 18:41 yp
[root@raptor ed]# 

The installation program is going to want to create and write into all
these directories, so your situation is not as clear-cut as my example of
/home.  You might consider booting your system single-user, and moving all
the existing system-level directories in /var out of the way, and then
doing the Red Hat Linux install -- that way, there won't be any possibility
of strange interactions when RPM starts writing stuff into /var...

There is also the issue as to whether a RAID 1 set created on Mandrake is
compatible with Red Hat Linux.  I would think that it is, but I'm not a
kernel hacker here, so I don't know for sure.

John> The amount of data and configuration files on this particular raid
John> set is so big that there is no way to back it up and re-deploy on a
John> fresh installation.

You have *no* way of backing up this data?  You must like living
dangerously.  I'd strongly recommend you address your backup-related issues
before you do anything else -- being able to get good backups (and the
ability to restore them) is *crucial*!  And no, your RAID1 mirror set
doesn't take the place of a backup -- just forget one day that you're in
/var, and type "rm -rf *", and you'll see what I mean... :-)

John> Further more the file system on this machine is ReiserFS.

It's my understanding that our kernels support ReiserFS for pre-existing
filesystems (ie, the installation program doesn't support ReiserFS-based
new installations), so you shouldn't be left with a filesystem you can't
read/write.

I will note that our kernel hackers did a lot of serious study of which
filesystems to support, and they felt that ReiserFS didn't meet the
standards they set at this time.  I know a lot of people use ReiserFS and
love it, but Red Hat Linux is a very conservative distribution when it
comes to data integrity, and personally, that's just fine with me... :-)

And do something about your backup situation -- if you run in this manner
long enough, you *will* get bitten by it...

                    I hope this helps,

                                Ed
-- 
Ed Bailey        Red Hat, Inc.          http://www.redhat.com/