# ezvzdump 

# Copyright (C) 2008 Alex Lance (alla at cyber.com.au)
# Sponsored by Silverband Pty. Ltd. 

# Modification by Rafael Darder Calvo (rdarder at spiralti.com)
 
# This program is free software: you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by the Free
# Software Foundation, either version 3 of the License, or (at your option) any
# later version.
 
# This program is distributed in the hope that it will be useful, but
# WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
# FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
# more details: http://www.gnu.org/licenses/gpl.txt
 

# Instructions 
# ------------

# This script rsyncs a VE to a specified local directory, suspends the running
# VE, rsyncs again, and then resumes the VE. This creates a stable snapshot of
# the VE directories with minimal downtime.

# Once the VE has been dumped out locally, it is rsynced to a remote host. When
# the rsync has completed, a tar archive is created on the remote host. The tar
# archive is compatible with the vzdump tar format, so the VE tar file may be
# later restored with the `vzdump --restore` command.

# By tarring the files together on the remote host, the burden of creating
# the tar archive is taken away from the hardware node, and given to the remote
# host / backup server. This ensures that minimal additional CPU/disk resources
# are used on the machine that is running the VE's.

# This script runs slow the first time you use it, but from then on it utilizes
# the local and remote stored snapshot directories so that the rsyncs happen
# expediently. The script does not wait for the remote tar process to complete,
# it simply kicks off the tar archive creation and then immediately continues.

# This script uses rsync and ssh and assumes that you already have ssh keys
# set up between your hosts. This script was written because vzdump takes too
# long and does not utilize a local cache, and also does not do network
# backups. This script also puts less strain on the hardware node by finishing
# backups more quickly, and making the remote host do the heavy lifting.

# NASTY BUG! Make sure you're not "vzctl enter"ing a VE while it's being
# suspended. On my machine (Ubuntu 2.6.24-24-openvz) it caused the VE to
# zombifiy and I had to reboot the host (including killing the VZ shutdown 
# script because it was unable to shutdown the VE/processes.) Just don't do it!

# usage: ezvzdump [-c config_file] [-s backup_set]