Release Notes for Relax-and-Recover version 1.18

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

Relax-and-Recover website

Github project

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:

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.

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

Version 1.18.0 (March 2016)

Version 1.17.2 (August 2015)

Version 1.17.1 (June 2015)

Version 1.17.0 (March 2015)

Version 1.16.1 (June 2014)

Version 1.16.0 (May 2014)

As usual lots of bug fixes - see the issue tracker.

Version 1.15.0 (September 2013)

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

As usual lots of bug fixes - see the issue tracker.

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


Relax-and-Recover (rear) is an Open Source project under GPL v3 license which means it is free to use and modify. However, the creators of rear have spend many, many hours in development and support. We will only give free of charge support in our free time (and when work/home balance allows it).

That does not mean we let our user basis in the cold as we do deliver support as a service (not free of charge).

Supported Operating Systems

Rear-1.18 is supported on the following Linux based operating systems:

Rear-1.18 dropped officially support for the following Linux based operating systems:

If you require support for unsupported Linux Operating System you must acquire a rear support contract (per system).

Requests to port rear to another Operating System (not Linux) can only be achieved with serious sponsoring.

Supported Architectures

Rear-1.18 is supported on:

Rear-1.18 may or may not fully work on:

Rear-1.18 does not support:

If you feel the need to get a fully functional rear working on one of the above mentioned type of processors please buy consultancy from one of our official developers.

Supported rear versions

Rear has a long history (since 2006) and we cannot supported all released versions anymore. If you have a problem we urge you to install the latest stable rear version or the development version (available on github) before submitting an issue.

However, we do understand that it is not always possible to install on hundreds of systems the latest and greatest version so we are willing to support previous versions of rear if you buy a support contract. Why do we change our policy? We cannot handle the big support requests anymore and we must give paid projects priority, therefore, we urge our customers to buy a support contract for one or more systems. You buy time with our core developers…

Known Problems and Workarounds

Issue Description: Debian 8 initramfs-tools: / on LVM gets mounted by initrd with kernel device name /dev/dm-X instead of /dev/mapper/XXX name

Issue #613 goes deeper into the problem with Debian 8 and LVM on /. The reporter created also a Debian Bug report #791754 for it.

See the fix mentioned in Debian Bug report #791754

Issue Description: BACKUP=NSR on RHEL 6 could break yum

Issue #387 describes a problem seen on RHEL 6 where when rear uses NSR and afterwards the link /lib64/ has been changed.

So far there is no workaround for this issue.

Issue Description: usage of an alternative configuration directory is different in mkbackup or recover mode

Using rear -v -c /etc/rear/mydir mkbackup works fine in production, but when you try (once booted from rescue image) rear -v -c /etc/rear/mydir recover it will fail.

The configuration files are copied to /etc/rear/ into the rescue image, so you simply need to type: rear -v recover See issue #512

Issue Description: Is there a possibility to add btrfs subvolume to a rsync backup

At present (release 1.18) there is no workaround in place. If you happen to know how this could be fixed then add your ideas to issue #417

Issue Description: UEFI ISO booting does not work on OpenSuSe 12.x, or SLES 11/12

At present (release 1.18.x) genisoimage cannot produce ISO images that can boot via UEFI on an OpenSuSe distribution (and also SLES). However, use the ebiso package instead to create UEFI ISO images on SLES.

Issue Description: TSM cp writing dangling symlink on SLES SP3

To fix the error (you might see):

ERROR [LipCopyTo] Could not copy '/usr/lib64/../../opt/tivoli/tsm/client/api/bin64/' to '/tmp/rear.10455/rootfs/lib64'

See issue 476 for the resolution.

Issue Description: System reconfiguration still has some weaknesses.

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 support incremental backups when we add the following extra variables:


Issue Description: ERROR: FindStorageDrivers called but STORAGE_DRIVERS is empty

Above error message might be seen after a fresh installation of the GNU/Linux kernel. Rear got confused between the running kernel version number and the actual fresh kernel available.

Reboot your server before using rear again, which is a good practice anyway after upgrading the GNU/Linux kernel.