Release Notes for Relax-and-Recover version 1.14.0

This document contains the release notes for the open source project Relax-and-Recover.

Relax-and-Recover website

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This document is distributed with the following license: “Creative Commons Attribution-NoDerivs 3.0 Unported (CC BY-ND 3.0)”. To read the license deed go to


Relax-and-Recover is a GNU/Linux system administrator tool used to create disaster recovery images which makes bare metal restore easier. System administrators use Relax-and-Recover as part of disaster recovery policy which does not replace in any way a good backup policy.

Product Features

The following features are supported on the most recent releases of Relax-and-Recover. Anything labeled as (NEW!) was added as the most recent release. New functionality for previous releases can be seen in the next chapter that details each release.

The most recent release of Relax-and-Recover is supported on most GNU/Linux based systems with kernel 2.6 or higher. It provides the following functionality:

Together with OUTPUT=USB we have now a complete solution on hard disks (booting of it and restoring data).

NOTE: Features marked experimental are prone to change with future releases.

Relax-and-Recover Releases

The first release of Relax-and-Recover, version 1.0, was posted to the web in July 2006. For each release, this chapter lists the new features and defect fixes. Note that all releases are cumulative, and that all releases of Relax-and-Recover are compatible with previous versions of Relax-and-Recover, unless otherwise noted.

Version 1.14.0 (September 2012)

The references pointing to fix#nr refer to our issues tracker

Lots of minor bugs were fixed, and not all of them are listed in current release notes. For a complete overview see the issue tracker.

Version 1.13.0 (April 2012)

Version 1.12.0 (November 2011)

Version 1.11.0 (May 2011)

Version 1.10.0 (February 2011)

An intermediate release only which fixed some hanging issues of version 1.9.0. Also, a RPM upgrade was fixed by this release from 1.7.25 to 1.9.0, which failed because of a wrongly CentOS symbolic link. See bugzilla#680664

Version 1.9.0 (February 2011)

With version 1.9.0 some new methods were added, such as:

Relax-and-Recover version 1.9.0 contain fixes for the following defects:

Version 1.7.26 (November 2010)

Relax-and-Recover version 1.7.26 fixed RedHat bugzilla defect 657174 : rescue image freezes during the boot while executing init. This was due the new upstart mechanism (replaced the sysv init procedure).

Version 1.7.25 (June 2010)

Relax-and-Recover version 1.7.25 fixed RedHat bugzilla defect 600217 : Fedora link missing in restore, pack and finalize sub-directories. This broke the proper image building on several Fedora versions.

System and Software Requirements

Relax-and-Recover works on GNU/Linux kernel with version 2.6 and higher. For lower kernel versions Relax-and-Recover cannot be used, and for these systems, mkcdrec is still a good alternative.

As Relax-and-Recover has been solely written in the bash language we need the bash shell which is standard available on all GNU/Linux based systems. The default backup program Relax-and-Recover uses is GNU/tar which is also standard available.

Relax-and-Recover is known to work well on x86 and x86_64 based architectures. Relax-and-Recover has also been ported to ia64 and ppc architectures, but these are less tested. Use the ‘rear validate’ command after every successful DR test please and mail us the results.

Choosing the best compression algorithm

The default backup program with Relax-and-Recover is (BACKUP_PROG=tar) GNU tar and the default compression used with tar is gzip. However, is using gzip the best choice? We have done some tests and published the results. See Relax-and-Recover compression tests

Known Problems and Workarounds

Issue Description: System reconfiguration still has some weaknesses.

Issue Description: The DHCP client is still a little rough around the edges, especially with complex networking scenarios.

Issue Description: An error is encountered while upgrading rear-1.7.* to rear-1.9.0:

error: unpacking of archive failed on file /usr/share/rear/finalize/CentOS: cpio: rename failed - Is a directory

First remove the older Relax-and-Recover version by hand and then install the new version. The local.conf is saved (as local.conf.rpmsave) when we execute rpm -e rear

Issue Description: If SELinux is not disabled during backup (variable BACKUP_SELINUX_DISABLE= in /etc/rear/local.conf) then we might see errors in the rear-$(hostname).log file such as:

tar: var/cache/yum/i386/15/updates/packages: Cannot setfilecon: No such file or directory

Make sure the BACKUP_URL destination understands extended attributes (CIFS is out of the question and NFS is problematic). When using local disks (or external USB devices) make sure the proper mount options are given in the BACKUP_OPTIONS variable, e.g.:


(TIP) BACKUP_SELINUX_DISABLE=1 variable has been introduced in the /usr/share/rear/conf/default.conf file to disable SELinux while the backup is running (default setting).

Issue Description: Is incremental backup possible? With our default settings (BACKUP=NETFS and BACKUP_PROG=tar) we do not support incremental backups.

However, when we change BACKUP_PROG=rsync we can use rear mkbackuponly option which is in fact an incremental backup using the rsync program. The same can be accomplished by using BACKUP=RSYNC and the proper BACKUP_URL=rsync://hostname/PATH.