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--- computing:storage:xen_backup.sh [2011/11/27 11:37]
gcooper created
+++ — (current)
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-====== xen_backup.sh ======
-<file>
-#!/bin/bash
-# xen_backup.sh by Gene Cooper (gcooper@sonoracomm.com)
-#
-# This script provides a fairly quick and clean method for backing up an OSS
-# Xen server.
-#
-# I searched for a tool to do this, but I couldn't find one...hence, this script.
-#
-# I use this script as a pre-exec script for my regular backup system.  Unfortunately,
-# there is downtime during the backup and amount of it will depend on the speed of your
-# hardware.  If you need better uptime than this script provides, you should look
-# into LVM snapshots.
-#
-# The logic of this script is simple and it is designed to minimize downtime.
-# It will determine the running Xen domains and then, one at a time, it will suspend each
-# domain, save (checkpoint) the running state, create a compressed copy of the disk image
-# file then resume the domain.  Afterward, your primary backup can be performed.
-#
-# IMPORTANT NOTE: This version of the script depends on sufficient free disk space to save
-# the gzip'd disk image files and the checkpoint (memory state) files!
-# The checkpoint files appear to be memory snapshots of the running domains and are the
-# size of the allocated memory.
-#
-# Your main backup should probably back up the /etc/xen directory, the compressed Xen disk
-# image files as well as the checkpoint files ($dest as set below).
-#
-# Restoring a domain from backup would mainly involve restoring the xen config files
-# from /etc/xen, restoring/uncompressing the disk image and checkpoint files to their
-# original locations then running a command like:
-#
-# xm restore /path/to/checkpointfile
-#
-# Log file
-log=/var/log/xen/xen_backup.log
-# Temp directory for checkpoint files
-dest=/vm/xen/backup
-# Xen configuration files location
-xenconfig=/etc/xen
-# Xen domains (VMs) to be backed up
-#alldomains=( dom1 dom2 dom3 dom4 )
-alldomains=( ISPConfig appserv mgmt )
-# Delete old backups - Assume they were backed up to tape or disk and are no longer needed
-# This may help keep your backups smaller by avoiding duplicate backups.
-delold=yes
-############## end of variables ################
-# Create temp dir if not exist
-if [ ! -d ${dest} ]
-then
-  echo "Temp directory for checkpoint files doesn't exist - creating..." >> $log
-  echo "" >> $log
- /bin/mkdir -p ${dest}
-fi
-# Subroutine Definitions
-delete-old()
-# Here we delete all old backups, if that is desirable.
-# This may help keep our tape backups smaller.
-{   if [ "$delold" = "yes" ]; then
-       rm -f $dest/*
-    fi
-}
-pre-backup()
-{
- echo "" >> $log
- /bin/date >> $log
- echo "Running pre-backup on running VMs (checkpointing)..." >> $log
- if [ -f $dest/$runningdomain.chk ]; then
-    echo "Deleting pre-existing checkpoint file $dest/$runningdomain.chk..." >> $log
-    rm -f $dest/$runningdomain.chk
- fi
- echo "Checkpointing the $runningdomain VM to $dest/$runningdomain.chk..." >> $log
- /usr/sbin/xm save $domain $dest/$runningdomain.chk >> $log
- /bin/date >> $log
-}
-compress-image()
-{
- echo "" >> $log
- /bin/date >> $log
-    # Now we create a compressed copy of the VM (.img file) ready to be backed up
-    # by the primary backup system.  I am not sure the next line will work in all cases
-    # to extract the .img filename from the xen config file, but it works on my domains.
-    imgfile=`cat $xenconfig/$domain |grep disk|cut -f3 -d ":"|cut -f1 -d ","`
-    echo "Compressing the $domain disk image file to $dest/$domain.img.gz..." >> $log
-    gzip -c $imgfile > $dest/$domain.img.gz
- /bin/date >> $log
-}
-post-backup()
-{
- echo "" >> $log
- /bin/date >> $log
- echo "Restoring the $domain domain to on-line status..." >> $log
- /usr/sbin/xm restore $dest/$domain.chk >> $log
- /bin/date >> $log
-}
-# Processing begins
-delete-old
-# Here we checkpoint only the currently running domains.
-for runningdomain in `xm list|grep -v Name|grep -v Domain-0|cut -f1 -d" "`; do
-   pre-backup
-   post-backup
-done
-# Here we back up all specified domains, not just running VMs.
-for domain in ${alldomains[@]}; do
-   compress-image
-done
-# Just closing out the log...
-echo "" >> $log
-echo "Backup Completed" >> $log
-/bin/date >> $log
-exit
-</file>

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