[K12OSN] Cloning Fedora mailproxy box

[James P. Kinney III]

On Fri, 2006-09-15 at 23:06 -0700, Marty Willie wrote:
> Hi all,
> 
> I'm what you would call a newbie to Linux.... My director of technology and Linux guru just accepted a position at Google and left the rest of us to tend to the Linux farm.
> 
> Mailproxy1 is currently running Fedora Core 5, and my objective is to create an image of this machine before it inevitably tips over and we have to put the pieces back together - Based on the tech dept’s current Linux knowledge, this would be a disaster. 
> 
> We have located an image of this machine from two years ago, however when we recently attempted to pull this image down onto what we had hoped would become mailproxy2, the machine would not boot. Can you image a Linux box running Fedora? If so, does the image have to be pushed down onto an identical set of hardware, as is the case with a Windows box?
> 
> Thanks in advance for any help you can supply.
> Marty
> 
> 
Welcome to the fun! Once you get used to how Linux does things, you'll
look back at how you used to do things and shake your head.

Disk images can work OK with Linux system as a means of
recovery/install. Once the image is restored to a new drive, usually the
bootloader (grub is used for Fedora and many others) needs to be
tweaked.

Yes, disk images need to be reinstalled onto very similar equipment. The
image process is best used for cloning identical systems (hence it's use
in large environments with many identical desktops). The big gotch would
be a 64-bit image installed on a 32-bit machine. It will never work.
With the AMD 64 bit (and the Intel newer 64 bit as well) a 32 bit OS can
run on the hardware.

Perhaps a better process is a regular backup scheme. Often it is easier
to to do a fresh install of the base OS, apply the updates from a local
repository and then restore the specific configuration files. For the
vast majority of server application on Fedora Core 5, the configuration
files are all in /etc. I highly recommend having a copy of "Unix Backup
and Recovery" from OReilly.

However, if you want to do a disk image process, get a second drive of
the same size and a live CD of some type of Linux system. Boot from the
live CD. Now run "dd if=/dev/hda of=/dev/hdd bs=512" and be prepared to
wait for a while. What this does is it makes a block-by-block copy of
the ENTIRE disk. It copies from the drive called /dev/hda (that would be
the IDE drive that is the Master on the first IDE controller) and copies
it to the drive /dev/hdd (the slave drive on the second IDE controller).
You will need to adjust the names to match you setup. If you have SATA
drives, the will seen as SCSI drives and will appear
as /dev/sda, /dev/sdb, etc. Be very careful about the "if" and "of"
designations. If they get reversed, well, bye-bye hard drive contents.

Once the copy is done, swap the drives out (put the copy in the place of
the original and pull out the original) and boot the box. It should come
up just fine. At that point, your done. Put the master drive in a static
proof bag on a shelf.

If you don't know what drives you have mounted where, the "mount"
command will tell you. The /etc/fstab file will also tell you how the
system expects to load up the filesystem (fstab= FileSystemTABle). A
good command to know to look at current hardware stuff is "dmesg" As it
will dump multiple screen loads very fast, it is usually run like "dmesg
|less" (that's the pipe sign "|"). Now the spacebar will advance on
screen and the PgUp will go back.

Another great book to have on the shelf is "Running Linux" by Matt
Welsh. It's in its 3rd edition (or maybe 4th). It is general "how to be
a linux sysadmin" information.

> 
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-- 
James P. Kinney III          
CEO & Director of Engineering 
Local Net Solutions,LLC        
770-493-8244                    
http://www.localnetsolutions.com

GPG ID: 829C6CA7 James P. Kinney III (M.S. Physics)
<jkinney at localnetsolutions.com>
Fingerprint = 3C9E 6366 54FC A3FE BA4D 0659 6190 ADC3 829C 6CA7
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