Release Notes for Relax-and-Recover version 2.5

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

Relax-and-Recover website

GitHub project

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Relax-and-Recover is a GNU/Linux system administrator tool and framework used to create bootable disaster recovery images which makes bare metal disaster recovery (including backup restore) easier. System administrators use the Relax-and-Recover framework to set up a disaster recovery procedure as part of their disaster recovery policy (which does not replace in any way a backup policy). Relax-and-Recover does not implement backup but complements it because backup (and restore) happens via external backup software that is only called by Relax-and-Recover.

Product Features

The following features are supported by 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. All releases are cumulative. Unless otherwise noted all releases of Relax-and-Recover are intended to work backward compatible with previous versions. In addition to the GPL disclaimer of warranty and liability there is no guarantee that things work backward compatible. In general the older the system is the less likely it is that a newer Relax-and-Recover version works. For each Relax-and-Recover version upgrade and for each change of a software that is used by Relax-and-Recover and for each change of your basic system you must re-validate that your disaster recovery procedure still works for you.

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

Version 2.5 (May 2019)


New features, bigger enhancements, and possibly backward incompatible changes:

Details (mostly in chronological order - newest topmost):

Version 2.4 (June 2018)


New features, bigger enhancements, and possibly backward incompatible changes:

Details (mostly in chronological order):

Many minor fixes (too many to list them all - use ‘git log’ to view them). A big thank you to all contributors as without you it would be impossible to keep up with the development in the Linux area. We love you all… :-)

Version 2.3 (December 2017)


New features and bigger enhancements:

Possibly backward incompatible changes:

Details (mostly in chronological order):

Version 2.2 (July 2017)

Version 2.1 (June 2017)

Version 2.00 (January 2017)

(Important Note) ReaR 2.00 introduced the 3-digits scripts instead of the 2-digits script. This means all scripts must begin with 3 digits, e.g. instead of 10-my-script. Therefore, if you wrote your own scripts make sure to renumber these. You could also use the make validate to check this.

Version 1.19.0 (October 2016)

Version 1.18.0 (March 2016)

Version 1.17.2 (August 2015)

Version 1.17.1 (June 2015)

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, x86_64 and ppc64(le) based architectures. Relax-and-Recover has also been ported to ia64 and arm 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 and Unsupported Operating Systems

We try to keep our wiki page Test Matrix rear 2.5 up-to-date with feedback we receive from the community.

ReaR-2.5 is supported on the following Linux based operating systems:

ReaR-2.5 dropped official support for the following Linux based operating systems:

ReaR-2.5 and ReaR-2.4 (and probably also some earlier versions) are known to no longer work reasonably well for the following Linux based operating systems:

If you require support for unsupported Linux Operating System you must acquire a ReaR support contract.

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

Supported and Unsupported Architectures

ReaR-2.5 is supported on:

ReaR-2.5 may or may not work on:

ReaR-2.5 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 support all released versions. 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 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: ‘rear’ package on Ubuntu 14.04 depends on isolinux package (which does not exist)

Read the comments in issue #1403

Issue Description: tar –test-label is not supported on Centos 5 who have tar version 1.15

Read the comments in issue #1014

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 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 and higher) 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: 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: 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.