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I need to create a full backup of a redhat server over a network. I have looked into a couple solutions such as dump and snapshot but neither seem like they would just give me a complete image of the server on a local machine.

Is there any software that will image an entire machine over a network allowing for a complete backup?

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There is no software I know of that will (reliably) image a running server: For an image backup to be viable you really need the machine to be quiescent (no changes being made to the disks you're imaging). Failure to quiesce the system may result in unreliable/unusable data in the images. If these images are going to be mission-critical, replace "may" with "Will. Maybe not the first time, or the second, but definitely the one time you NEEDED it to work."
That said, you can boot into a recovery disk or LiveCD and use dd piped over SSH, or look into something like g4u to do the job with a little more polish. If you're imaging with the intent to virtualize, your virtualization platform provider probably has tools specifically designed for this task.

If you have LVM set up you may be able to do the same thing with LVM snapshots, but the reliability is slightly lower than taking an image of a system that has been properly shut down (you may kick off the snapshot in the middle of a database write for example).


Note that while taking full-disk images is a valid backup method it is insanely time-consuming and difficult to manage, and taking the system to a state where you can do the backup usually entails an outage. If you want backups (something that you do periodically to guard against data loss) you are almost certainly better off investigating backup software - I suggest Bacula for *NIX environments.

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I am currently using bacula enterprise to do BMR (Bare metal recovery) live which is what you are looking for. I believe that the open source version has similar funtionality as well.

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OK, I assume that you can take down the server. I have used the following process before.

  1. Reboot the system (or from the CD) into single user mode.
  2. If you have an LVM, then activate the Volume group where the partitions that need to be dumped are located.
  3. Configure the network interface manually.
  4. I like using dump to do backups because generally they are just as easily restored using restore. Further dump processes the bacakup at a level closer to the filesystem, so that sparse files are truely dumped and restored as such. Do it like dump 0fds - 99999 99999 /dev/sda1 | gzip | ssh user@hostname 'cat >filename.dmp.gz'

I'm of course assuming that you have ext2 or ext3 mountable areas.

I'm not a fan of dd, in that it locks in a lot of partition information that I don't need and generally it is larger than the dump output. Upon restoration of this stuff to a new server, you will have to use the grub command to properly initialize the boot sector.

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