[CentOS] Best way to duplicate a live Centos 5 server?

Tue Jun 19 17:44:33 UTC 2012
Les Mikesell <lesmikesell at gmail.com>

On Tue, Jun 19, 2012 at 12:03 PM, Cal Sawyer <cal-s at blue-bolt.com> wrote:
> You're right - documentation is pretty dire.  Guess i'm not alone in
> hating doing it.

Yes, I really, really wish the stuff they are doing was documented,
somewhere, anywhere.  Not just how to use the program itself which is
supposed to 'just work' unattended once you set it up, but the black
magic of how they detect and reproduce all of the hardware, lvm, raid,
filesystem, etc. across different distributions and versions.

> USB backup is broken due to the order in which path variables get set -
> sure is lot of fun trawling through the scripts to find out what gets
> set when.  Hope the ReaR maintainers are interested in this and haven't
> gotten themselves mired in tape
> archive integration - i would have thought USB backup was the winner in
> terms of getting broad acceptance as a bare-metal DR solution.

USB is sort of 'hands-on' for something that should be unattended, and
adds a lot of unpredictable messiness in drive detection, boot order,
etc.    All you really have to do is export some NFS space and point
ReaR to it.  At least that is the easy way to get started.  If you
have another Linux box, just plug your USB drive in there and access
it over NFS...  problem solved.

Clonezilla-live plays in this space too, but it doesn't do raid or
multiple disks at once, and you have to shut down to take the image.

My 'ideal' system would be to  have ReaR generate a directory of what
will be on the boot iso leaving that somewhere on the host without
actually making the image.   Then use backuppc to back up the whole
host and its normal duplicate-pooling mechanism will keep the extra
copies of the tools from taking extra space.  Then when/if you need a
bare-metal restore, you would first grab the directory of the iso
contents, burn a boot CD, let that reconstruct the filesystem, then
tell backuppc to restore to it.  That way would be completely
automatic and always be up to date, with the advantage of backuppc's
efficient storage and easy online access to individual files and
directories.   If you don't mind wasting a small amount of space for
the isos, I think that approach would already work if you tell ReaR to
just make the boot image and to wait for an external program to do the
restore after the filesystem has been rebuilt.

> However, when it works - wow.  Just restored an HP dl360 w/HWRAID to a
> Presario desktop machine and it lives!  No network, but that's small
> beans compared to the larger win.

Yes, I've even modified the filesystem layout file to go from a
software RAID to a non-RAID, and to change partition sizes during the
restores.   If it was documented, that capability by itself would be

    Les Mikesell
     lesmikesell at gmail.com