[SATLUG] Live backup / hot imaging software for Linux?

John Pappas j at jvpappas.net
Sat Feb 5 19:30:42 CST 2011


On Thu, Feb 3, 2011 at 15:19, David Salisbury <
david.salisbury at momentumweb.com> wrote:

> Can anyone recommend a good backup software that can clone an entire drive
> into an image while said drive is running?  Something like DriveImageXML,
> but for Linux.  I've tried just copying partition-to-partition (/dev/hda to
> /dev/hdb, for example) and using dd, with somewhat mixed and unpredictable
> results on the copy.  What is the best way to get a hot image of a disk in
> Linux?
> David
>

Assume FOSS: Acronis supports Linux, but is not FOSS.

dd won't result in a consistent point in time copy, so files and the
filesystem continue to change while the backup is running.  You won't end up
with a "crash consistent" backup, so not really what you are looking for.

Matthew's reference to LVM is the best, as it uses a Copy on Write
snapshotting method, but requires said partitions be LVM, and moving from
static root to LVM root is non-trivial.  I only install linux with LVM as it
allows for so much magic that I cannot stand static partitions for anything
but /boot and swap for laptop hibernation (thus my disks are
/dev/sd?1=/boot; /dev/sd?2=swap at 2xRAM; /dev/sd?3=LVM), and then at least LV
for root, home, additional swap (if needed), and any other breakout required
by the application (var, usr, opt, whatever)

In terms of a on-the-fly imager (ala Acronis or DIX) for static
partitions/disks, you need something that has/provides/uses snapshotting or
similar.  I have no direct experience with any non-LVM snapshotting for
Linux, as most use cases allow for cold-clone so live snapshots gain little
benefit.  For those use cases where live clone is needed, I use LVM.

I look forward to other's feedback and the potential solution (can't have
too many tools in one's toolbelt).

John


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