Re: [Trinux-talk] Q - Timothy Burt - Backup or clone hard drive

[Timothy B. <tb...@ar...>]

The CD creation process currently separates the "building of the iso 
filesystem" from the "burning of the cd".  This is because the 
building of the iso usually impacts the burn, and the burn can fail due to 
the pipeline becoming empty, or because of cpu/disk load gets too high.

So, you need to perform your backup to cd in two phases.  The creation of 
the iso filesystem from the current disk (creating an image), and then 
burn the image to CD.  You can burn the image to CD with any OS, including 
windows.  The task is to create the image.

Ideally, you want the image created from a quiet filesystem, not one that 
is the root of a running multi-user mode UNIX.  I have accomplished this 
by running in single user mode, but this failed for some reason on some 
recent RH releases, so I now mount the filesystem to be backed up on the 
/mnt of a running OS.  And I use Trinux as the running OS, on which to 
mount my filesystem.

With the hard disk mounted on /mnt, the challange now becomes where to put 
the data that gets dumped into the image file.  Ideally, this should be on 
a filesystem other than the filesystem that is being backed up.  Although 
with some effort, you might be able to create your image and skip the 
image file itself.  See below.

In my previous description, this problem was solved by physically mounting 
the new disk onto the controller.  Mount them both, and copy from one to 
the other.  But in this scenario, we do not have a new disk to use, 
because we are building an ISO that we can later burn to a CD.

Some options you may have available include:

1) attach a spare hard disk, and build your iso on it.
2) use an nfs mounted filesystem, but could be really slow.
3) use a modified buildiso command (find |grep -v isofilename.iso | 
mkisofs) that strips out the iso filename.

Which choice may depend on your resources and the speed with which you 
need to accomplish the task...

If the machine is an internet server, then you want this to happen fast, 
so I would suggest option 1 (or 3).  A permanently mounted extra 
filesystem would be ideal.  You may need to go single user, while the 
backup happens, but this could be for as little as a minute or two.  Or up 
to 30 YMMV.

If it is an internal office server that is totally quiet and unused at 
times of the day, then you could easily use option 2, as often as you 
like.

Of Course....  Once you have a copy of your root filesystem imaged onto 
the CD, then it is a simple task to boot from Trinux, mount the hard disk, 
and mount the cd and do a find . -print | cpio -pmduv /mnt/harddisk.. 
Sometimes you need a quick lilo to make it boot.

This is an excellent mechanism for preserving the state of a known good 
running machine.  It can be done on a regular basis, and efficiently 
stored off site.  It might also be accomplished nightly.  I highly 
recommend it.

FINAL HINT -- I haven't ever done what is described, so I don't have the 
exact commands, but it should work.  Also, you might also consider burning 
an image to the CD that is NOT ISO, but a more Unix friendly FS.  This may 
help preserve ownership and perms issues, if you encounter any.  ISO, as a 
standard, does not preserve UNIX perms. (correct me if I am wrong, please)

On Wed, 2 Oct 2002, Riaan Labuschagne wrote:

> 
> Timothy,
> I refer to your "clone hard drive" howto you wrote.
> 
> Is there a way that I can tar the contents of a backed up disc, copy it to
> cd, untar it on a partition on the new hard drive and restore the disc,
> whilts keeping the permissions etc?
> 
> I AM NOT LOOKING for a howto, just some pointers please.
> 
> Thanks
> Riaan Labuschagne
> 
> P.S. Trinux is helping my business www.radioretail.co.za a hell of allot. I
> am in the process of upgrading 430 WinNT machines   to  Debian without any
> human intervention. (no keyboard , mouse or screens on the machines.)
> 
> ri...@ra...
> 
> 
> 
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-- 
--------------------
Timothy Burt
General Manager
Arbor Group LLC
Los Angeles, Calif. USA