Backup with duplicity
From OpenKM Documentation
duplicity backs directories by producing encrypted tar-format volumes and uploading them to a remote or local file server. Because duplicity uses librsync, the incremental archives are space efficient and only record the parts of files that have changed since the last backup. Because duplicity uses GnuPG to encrypt and/or sign these archives, they will be safe from spying and/or modification by the server.
Duplicity can be installed in Debian / Ubuntu as simple as:
$ sudo aptitude install duplicity
But it not in the CentOS / RedHat default repositories, so you need to install from another source. This script will help in this installation process:
#!/bin/bash
#ARCH=i386
ARCH=x86_64
wget http://download.fedora.redhat.com/pub/epel/5/$ARCH/duplicity-0.6.14-1.el5.$ARCH.rpm
wget http://download.fedora.redhat.com/pub/epel/5/$ARCH/ncftp-3.2.2-1.el5.$ARCH.rpm
wget http://download.fedora.redhat.com/pub/epel/5/$ARCH/librsync-0.9.7-13.el5.$ARCH.rpm
wget http://download.fedora.redhat.com/pub/epel/5/$ARCH/python-GnuPGInterface-0.3.2-2.el5.noarch.rpm
wget http://download.fedora.redhat.com/pub/epel/5/$ARCH/python-boto-1.9b-6.el5.noarch.rpm
rpm -Uvh duplicity-0.6.14-1.el5.$ARCH.rpm ncftp-3.2.2-1.el5.$ARCH.rpm librsync-0.9.7-13.el5.$ARCH.rpm python-GnuPGInterface-0.3.2-2.el5.noarch.rpm python-boto-1.9b-6.el5.noarch.rpm