Getting started with ReaR¶

Relax-and-Recover (ReaR) is a DR tool written for GNU/Linux, but as we all know there are hundreds of GNU/Linux variants and we do our best to support the majorty of them. However, keep in mind we cannot please everybody.

Software requirements¶

Relax-and-Recover aims to have as little dependencies as possible, however over time certain capabilities were added using utilities and specific features, causing older distributions to fall out of support. We try to avoid this where practically possible and be conservative to add new dependencies.

The most basic requirement for Relax-and-Recover is having bash, and ubiquitous Linux tools like:

• dd (coreutils)
• ethtool
• file
• grep
• gzip
• ip (iproute[2])
• mount (util-linux-ng)
• ps (procps)
• sed
• ssh (openssh-clients)
• strings (binutils)
• tar
• ...

Optionally, some use-cases require other tools:

• lsscsi and sg3_utils (for OBDR tape support)
• mkisofs or genisoimage (for ISO output support)
• syslinux (for ISO or USB output support)
• syslinux-extlinux (for USB support)
• ebiso (for SLES UEFI booting)

In some cases having newer versions of tools may provide better support:

• syslinux >= 4.00 (provides menu support)
• parted

In case we are using BACKUP=NETFS with nfs or cifs we might need also:

• nfs-client
• cifs-utils

Distribution support¶

As a project our aim is not to exclude any distribution from being supported, however (as already noted) some older distributions fell out of support over time and there is little interest from the project or the community to spend the effort to add this support.

On the other hand there is a larger demand for a tool like Relax-and-Recover from the Enterprise Linux distributions, and as a result more people are testing and contributing to support those distributions.

Currently we aim to support the following distributions by testing them regularly:

• Red Hat Enterprise Linux and derivatives: RHEL6, RHEL7 and RHEL8
• SUSE Linux Enterprise Server 12 and 15
• Ubuntu LTS: 17, 18, 20

Distributions dropped as supported:

• Ubuntu LTS <17
• Fedora <29
• RHEL 3, 4 and 5
• SLES <12
• openSUSE <11
• Debian <8

Distributions known to be 'unsupported' are:

• Ubuntu LTS 8.04 (as it does not implement grep -P)

Known limitations¶

Relax-and-Recover offers a lot of flexibility in various use-cases, however it does have some limitations under certain circumstances:

• Relax-and-Recover depends on the software of the running system. When recovering this system to newer hardware, it is possible that the hardware support of the original system does not support the newer hardware.

• Relax-and-Recover supports recovering to different hardware, but it cannot always automatically adapt to this new environment. In such cases it requires a manual intervention to e.g.

  • modify the disklayout.conf to indicate the number of controller, disks or specific custom desires during restore

  • reduce the partition-sizes/LV-sizes when restoring to smaller storage

  • pull network-media or configure the network interfaces manually

• Depending on your back-up strategy you may have to perform actions, like:

  • insert the required tape(s)

  • perform commands to restore the backup

Installation¶

You can find the RPM and DEB packages from our web site at https://relax-and-recover.org/download/

The latest stable versions of Fedora and SLES can be installed via yum (on RHEL 6 and 7), or via dnf (on RHEL 8) or zypper (on SLES). However, keep in mind, when you download ReaR from the vendors repositories that the version of ReaR is not always the latest version and will vary from the upstream version. Furthermore, if you have problems with the vendors version of ReaR please contact the vendor directly via their support channels. If required the vendor will contact us via the upstream channels (through our GitHub issues).

On our download pages you will find two sections (stable and snapshot versions) of ReaR packages. Select the stable section if you want to play it safe, or the snapshot section if you have issues with a stable version as the snapshot versions are nightly rebuild and may or may not contain your fixes. Please check the current issues submitted at GitHub to check if your problem has already been reported.

From downloaded RPM packages¶

Simply install (or update) the provided packages using the command: rpm -Uhv rear-2.6-1.el8.x86_64.rpm

You can test your installation by running rear dump:

[root@system ~]# rear dump
System definition:
                                    ARCH = Linux-x86_64
                                      OS = GNU/Linux
                               OS_VENDOR = RedHatEnterpriseServer
                              OS_VERSION = 8.2

From DEB packages¶

On a Debian system (or Ubuntu) you can download the DEB packages from our download page and install it with the command:

dpkg -i rear*.deb

On Debian (Ubuntu) use the following command to install missing dependencies:

apt-get -f install

From source¶

The latest and greatest sources are available at GitHub location : https://github.com/rear/rear

To make local copy with our github repository just type:

git clone git@github.com:rear/rear.git

File locations¶

Remember the general configuration file is found at /usr/share/rear/conf/default.conf. In that file you find all variables used by rear which can be overruled by redefining these in the /etc/rear/site.conf or /etc/rear/local.conf files. Please do not modify the default.conf file itself, but use the site.conf or local.conf for this purpose.