rear man page

rear — bare metal disaster recovery and system migration tool

Synopsis

rear [-h|--help] [-V|--version] [-dsSv] [-D|--debugscripts SET] [-c DIR] [-r KERNEL] [--] COMMAND [ARGS...]

Description

Relax-and-Recover is the leading Open Source disaster recovery solution. It is a modular framework with many ready-to-go workflows for common situations.

Relax-and-Recover produces a bootable image. This image can repartition the system. Once that is done it initiates a restore from backup. Restores to different hardware are possible. Relax-and-Recover can therefore be used as a migration tool as well.

Currently Relax-and-Recover supports various boot media (incl. ISO, PXE, OBDR tape, USB or eSATA storage), a variety of network protocols (incl. sftp, ftp, http, nfs, cifs) for storage and backup as well as a multitude of backup strategies (incl. IBM Tivoli Storage Manager, HP DataProtector, Symantec NetBackup, EMC NetWorker, FDR/Upstream, NovaBACKUP DC, Bareos, Bacula, rsync, rbme). This results in a bootable image that is capable of booting via PXE, DVD/CD, bootable tape or virtual provisioning.

Relax-and-Recover was designed to be easy to set up, requires no maintenance and is there to assist when disaster strikes. Its setup-and-forget nature removes any excuses for not having a disaster recovery solution implemented.

Recovering from disaster is made very straight-forward by a 2-step recovery process so that it can be executed by operational teams when required. When used interactively (e.g. when used for migrating systems), menus help make decisions to restore to a new (hardware) environment.

Extending Relax-and-Recover is made possible by its modular framework. Consistent logging and optionally extended output help understand the concepts behind Relax-and-Recover and help debug during development.

Relax-and-Recover comes with ABSOLUTELY NO WARRANTY; for details see the GNU General Public License at: http://www.gnu.org/licenses/gpl.html

Options

Global Options

-h --help

usage information

-c DIR

alternative config directory; instead of /etc/rear

-d

debug mode (log debug messages to log file)

-D

debugscript mode (log every function call via set -x)

--debugscripts SET

same as -d -v -D but debugscript mode with set -SET

-r KERNEL

kernel version to use (by default use running kernel)

-s

simulation mode (show what scripts rear would include)

-S

step-by-step mode (acknowledge each script individually)

-v

verbose mode (show progress output)

-V --version

version information

Commands

checklayout

check if the disk layout has changed since the last run of mkbackup/mkrescue

dump

dump configuration and system information; please run this to verify your setup

format

format and label USB or tape media to be used with rear;

first argument is the USB or tape device to use, eg. /dev/sdX or /dev/stX

help

print full list of commands and options

mkbackup

create rescue media and backup the system (only for internal backup methods)

mkbackuponly

backup the system (only for internal backup methods) without creating rescue media

mkrescue

create rescue media only

recover

recover the system; can be used only when running from the rescue media

validate

submit validation information

Use rear -v help for more advanced commands.

Background Information

The process of bare metal disaster recovery consists of two parts:

· Recreate the system layout

· Restore the data to the system

Most backup software solutions are very good at restoring data but do not support recreating the system layout. Relax-and-Recover is very good at recreating the system layout but works best when used together with supported backup software.

In this combination Relax-and-Recover recreates the system layout and calls the backup software to restore the actual data. Thus there is no unnessecary duplicate data storage and the Relax-and-Recover rescue media can be very small.

For demonstration and special use purposes Relax-and-Recover also includes an internal backup method, NETFS, which can be used to create a simple tar.gz archive of the system. For all permanent setups we recommend using something more professional for backup, either a traditional backup software (open source or commercial) or rsync with hardlink based solutions, e.g. RSYNC BACKUP MADE EASY.

Rescue Image Configuration

The OUTPUT variable defines from where our bootable rescue image will be booted and the OUTPUT_URL variable defines where the rescue image should be send to. Possible OUTPUT setting are:

OUTPUT=RAMDISK

Create only the Relax-and-Recover initramfs.

OUTPUT=ISO

(Default) Create a bootable ISO9660 image on disk as rear-$(hostname).iso

OUTPUT=PXE

Create on a remote PXE/NFS server the required files (such as configuration file, kernel and initrd image

OUTPUT=OBDR

Create a bootable OBDR tape (optionally including the backup archive). Specify the OBDR tape device by using TAPE_DEVICE.

OUTPUT=USB

Create a bootable USB disk (using extlinux). Specify the USB storage device by using USB_DEVICE.

When using OUTPUT=ISO, RAMDISK, OBDR or USB you should provide the backup target location through the OUTPUT_URL variable. Possible OUTPUT_URL settings are:

OUTPUT_URL=file://

Write the image to disk. The default is in /var/lib/rear/output/.

OUTPUT_URL=fish://

Write the image using lftp and the FISH protocol.

OUTPUT_URL=ftp://

Write the image using lftp and the FTP protocol.

OUTPUT_URL=ftps://

Write the image using lftp and the FTPS protocol.

OUTPUT_URL=hftp://

Write the image using lftp and the HFTP protocol.

OUTPUT_URL=http://

Write the image using lftp and the HTTP (PUT) procotol.

OUTPUT_URL=https://

Write the image using lftp and the HTTPS (PUT) protocol.

OUTPUT_URL=sftp://

Write the image using lftp and the secure FTP (SFTP) protocol.

OUTPUT_URL=rsync://

Write the image using rsync and the RSYNC protocol.

OUTPUT_URL=sshfs://

Write the image using sshfs and the SSH protocol.

OUTPUT_URL=null

Do not copy the ISO image from /var/lib/rear/output/ to an external destination. Useful in combination with an external backup program, or when BACKUP_URL=iso://backup

The ISO_DEFAULT variable defines what default boot option is used on the rescue image. Possible values are manual, boothd or unattended. Manual will make you boot into the shell directly by default, boothd will boot to the first disk (default) or unattended will automatically start in recovery mode.

Backup Software Integration

Currently Relax-and-Recover supports the following backup methods. Please distinguish carefully between Relax-and-Recover support for 3rd party backup software and Relax-and-Recover internal backup methods. The latter also creates a backup of your data while the former will only integrate Relax-and-Recover with the backup software to restore the data with the help of the backup software without actually creating backups. This means that for all non-internal backup software you must take care of creating backups yourself.

Especially the rear mkbackup command can be confusing as it is only useful for the internal backup methods and has no function at all with the other (external) backup methods.

The following backup methods need to be set in Relax-and-Recover with the BACKUP option. As mentioned we have two types of BACKUP methods - internal and external.

The following BACKUP methods are external of Relax-and-Recover meaning that you are responsible of backups being made:

BACKUP=REQUESTRESTORE

(default) Not really a backup method at all, Relax-and-Recover simply halts the recovery and requests that somebody will restore the data to the appropriate location (e.g. via SSH). This method works especially well with an rsync based backup that is pushed back to the backup client.

BACKUP=EXTERNAL

Internal backup method that uses an arbitrary external command to create a backup and restore the data.

BACKUP=DP

Use HP Data Protector to restore the data.

BACKUP=FDRUPSTREAM

Use FDR/Upstream to restore the data.

BACKUP=GALAXY

Use CommVault Galaxy 5 to restore the data.

BACKUP=GALAXY7

Use CommVault Galaxy 7 to restore the data.

BACKUP=GALAXY10

Use CommVault Galaxy 10 (or Simpana 10) to restore the data.

BACKUP=NBU

Use Symantec NetBackup to restore the data.

BACKUP=TSM

Use IBM Tivoli Storage Manager to restore the data. The Relax-and-Recover result files (e.g. ISO image) are also saved into TSM.

BACKUP=NSR

Using EMC NetWorker (Legato) to restore the data.

BACKUP=SESAM

Using SEP Sesam to restore the data.

BACKUP=NBKDC

Using Novastor NovaBACKUP DC to restore the data.

BACKUP=RBME

Use Rsync Backup Made Easy (rbme) to restore the data.

BACKUP=BAREOS

Use Open Source backup solution BAREOS (a fork a BUCULA) to restore the data.

BACKUP=BACULA

Use Open Source backup solution BACULA to restore the data.

BACKUP=DUPLICITY

Use encrypted bandwidth-efficient backup solution using the rsync algorithm to restore the data.

The following BACKUP methods are internal of Relax-and-Recover:

BACKUP=NETFS

Internal backup method which can be used to create a simple backup (tar archive).

BACKUP=RSYNC

Use rsync to restore data.

If your favourite backup software is missing from this list, please submit a patch or ask us to implement it for you.

When using BACKUP=NETFS you should provide the backup target location through the BACKUP_URL variable. Possible BACKUP_URL settings are:

BACKUP_URL=file://

To backup to local disk, use BACKUP_URL=file:///directory/path/

BACKUP_URL=nfs://

To backup to NFS disk, use BACKUP_URL=nfs://nfs-server-name/share/path

BACKUP_URL=tape://

To backup to tape device, use BACKUP_URL=tape:///dev/nst0 or alternatively, simply define TAPE_DEVICE=/dev/nst0

BACKUP_URL=rsync://

When backup method BACKUP=RSYNC is chosen then we need to define a corresponding BACKUP_URL rule:

BACKUP_URL=rsync://[user@]host[:port]/path
BACKUP_URL=rsync://[user@]host[:port]::/path

BACKUP_URL=cifs://

To backup to a Samba share (CIFS), use BACKUP_URL=cifs://cifs-server-name/share/path. To provide credentials for CIFS mounting use a /etc/rear/cifs credentials file and define BACKUP_OPTIONS="cred=/etc/rear/cifs" and pass along:

username=_username_
password=_secret password_
domain=_domain_

BACKUP_URL=usb://

To backup to USB storage device, use BACKUP_URL=usb:///dev/disk/by-path/REAR-000 or use a real device node or a specific filesystem label. Alternatively, you can specify the device using USB_DEVICE=/dev/disk/by-path/REAR-000.

If you combine this with OUTPUT=USB you will end up with a bootable USB device.

BACKUP_URL=sshfs://

To backup to a remote server via sshfs (SSH protocol), use BACKUP_URL=sshfs://user@remote-system.domain.org/home/user/backup-dir/

It is advisable to add ServerAliveInterval 15 in the /root/.ssh/config file for the remote system (remote-system.domain.org).

BACKUP_URL=iso://

To include the backup within the ISO image. It is important that the BACKUP_URL and OUTPUT_URL variables are different. E.g.

BACKUP_URL=iso:///backup/
OUTPUT_URL=nfs://server/path/

When using BACKUP=NETFS there is an option to select a BACKUP_TYPE=incremental to have rear make incremental backups until the next full backup e.g. via FULLBACKUPDAY="Mon" is reached. The current implementation supports only to restore one full backup plus one single incremental backup so that currently BACKUP_TYPE=incremental actually implements a differential backup.

Configuration

To configure Relax-and-Recover you have to edit the configuration files in /etc/rear/. All *.conf files there are part of the configuration, but only site.conf and local.conf are intended for the user configuration. All other configuration files hold defaults for various distributions and should not be changed.

In /etc/rear/templates/ there are also some template files which are used by Relax-and-Recover to create configuration files (mostly for the boot environment). Modify the templates to adjust the information contained in the emails produced by Relax-and-Recover. You can use these templates to prepend your own configurations to the configuration files created by Relax-and-recover, for example you can edit PXE_pxelinux.cfg to add some general pxelinux configuration you use.

In almost all circumstances you have to configure two main settings and their parameters: The backup method and the output method.

The backup method defines, how your data was saved and wether Relax-and-Recover should backup your data as part of the mkrescue process or wether you use an external application, e.g. backup software to archive your data.

The output method defines how the rescue system is written to disk and how you plan to boot the failed computer from the rescue system.

See the default configuration file /usr/share/rear/conf/default.conf for an overview of the possible methods and their options.

An example to use TSM for backup and ISO for output would be to add these lines to /etc/rear/local.conf (no need to define a BACKUP_URL when using an external backup solution):

BACKUP=TSM
OUTPUT=ISO

And if all your systems use NTP for time synchronisation, you can also add these lines to /etc/rear/site.conf

TIMESYNC=NTP

Do not forget to distribute the site.conf to all your systems.

The resulting ISO image will be created in /var/lib/rear/output/. You can now modify the behaviour by copying the appropriate configuration variables from default.conf to local.conf and changing them to suit your environment.

Exit Status

0

Successful program execution.

>0

Usage, syntax or execution errors. Check the log file in /var/log/rear/ for more information.

Examples

To print out the current settings for BACKUP and OUTPUT methods and some system information. This command can be used to see the supported features for the given release and platform.

# rear dump

To create a new rescue environment. Do not forget to copy the resulting rescue system away so that you can use it in the case of a system failure.

# rear -v mkrescue

To create a new rescue image together with a complete archive of your local system run the command:

# rear -v mkbackup

Files

/usr/sbin/rear

The program itself.

/etc/rear/local.conf

System specific configuration can be set here.

/etc/rear/site.conf

Site specific configuration can be set here (not created by default).

/var/log/rear/

Directory holding the log files.

/tmp/rear.####

Relax-and-Recover working directory. If Relax-and-Recover exits with an error, you must remove this directory manually.

/usr/share/rear

Relax-and-Recover script components.

/usr/share/rear/conf/default.conf

Relax-and-Recover default values. Contains a complete set of parameters and its explanation. Please do not edit or modify. Copy values to local.conf or site.conf instead.

Bugs

Feedback is welcome, please report any issues or improvements to our issue-tracker at: http://github.com/rear/issues/

Furthermore, we welcome pull requests via GitHub.

See Also

Relax-and-Recover comes with extensive documentation located in /usr/share/doc.

Authors

Gratien Dhaese, Schlomo Schapiro, Johannes Meixner, Jeroen Hoekx and Dag Wieers.

Lars Pinne (original man page).

Relax-and-Recover is a collaborative process using Github at: http://github.com/rear/

The Relax-and-Recover website is located at: http://relax-and-recover.org/

Info

05 August 2016