vzdump

vzdump of CentOS

Current versions of vzdump has dependency for cstream and perl-LockFile-Simple, both available via rpmforge. Below is how I got it to install and run on CentOS-5.5 x86_64 architecture.

wget http://packages.sw.be/rpmforge-release/rpmforge-release-0.5.1-1.el5.rf.x86_64.rpm
rpm -ivh rpmforge-release-0.5.1-1.el5.rf.x86_64.rpm
yum --enablerepo=rpmforge install cstream perl-LockFile-Simple
rpm -ivh http://download.openvz.org/contrib/utils/vzdump/vzdump-1.2-4.noarch.rpm

It's necessary to export the location of the PVE libraries that vzdump requires. This can be added to ".bash_profile":

export PERL5LIB=/usr/share/perl5/

vzdump LVM snapshots kernel errors

On running daily lvm snapshot backups via vzdump on OpenVZ servers, I noticed the below Kernel errors in logwatch reports.


WARNING:  Kernel Errors Present
    Buffer I/O error on device dm-4,  ...:  22 Time(s)
    EXT3-fs error (device dm-4): e ...:  60 Time(s)
    lost page write due to I/O error on dm-4 ...:  22 Time(s)

This would show up on busy servers only, probably caused due to lvm snapshot running out of space.

I edited "/usr/bin/vzdump" and increased the size from 500m to 1000m which seems to have resolved the issue for now.


run_command (\*LOG, "$lvcreate --size 1000m --snapshot --name vzsnap /dev/$lvmvg/$lvmlv");

Weekly backups of all OpenVZ container

Here's is a simple shell script to run a weekly lvm snapshot dump of all OpenVZ containers using the vzdump utility:

#!/bin/bash
# ve_dumps.sh
# Dump all VEs

# Todays' date
DATE=$(date +%d)

# Paths
BAK_PATH=/opt/bak/vz_dumps
# Week of month
BAK_DIR=$(cal | awk -v date="${DATE}" '{ for( i=1; i <= NF ; i++ ) if ($i==date) { print FNR-2 } }')

# Function to check and remove previously failed snapshot.
check_vzsnap() {
  OUTPUT=`/usr/sbin/lvdisplay | grep vzsnap`
  [ -n "$OUTPUT" ] && lvremove -f /dev/vg0/vzsnap
}

# Function to perform backup.
backup() {
  # Check and create the required backup directory
  [ -d "${BAK_PATH}/${BAK_DIR}" ] || mkdir -p ${BAK_PATH}/${BAK_DIR}
  # do dumps
  echo "Starting dump at `date`"
  /usr/bin/vzdump --exclude-path '.+/log/.+' --exclude-path '.+/bak/.+' --exclude-path '/tmp/.+' --exclude-path '/var/tmp/.+' --exclude-path '/var/run/.+pid' --snapshot --dumpdir=${BAK_PATH}/${BAK_DIR} --compress --all
  echo "Completed dump at `date`"
}

# Main ############################

# Remove previously failed snapshot
check_vzsnap

# Run backups
backup

exit 0

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