[CentOS] backup server..

Will McDonald wmcdonald at gmail.com
Thu Sep 14 08:28:05 UTC 2006

On 14/09/06, Sebastien Tremblay <sebastien.tremblay at au.cmpmedica.com>
> I know there is none at the moment which
> is why I was looking into dd and tar. I've read that dd physically
> read/write every blocks of the disk whereas tar handles `zero-files`
> differently... Thus my question!

I suspect dd-ing from an active disk isn't necessarily the best of
ideas. You can:

# dd if=/dev/sda of=/dev/sdb

... one identical disk to another, or at least to another with the
same geometry. If both disks are unmounted you'll get a consistent
snap-shot of the system.

Doing similar with an active, mounted /dev/sda on a running system
wouldn't guarantee the consitancy of the "backup". I think you'd be
better partitioning up your disks similarly and tar-ing, though you
mention 'zero-files', do you mean sparse files? In which case special
measure may be required for those?


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