Usage scenarios
Recovery from USB
Prepare your rescue media using
rear format /dev/sdX
It will be labeled REAR-000. The /etc/rear/local.conf can be as simple as:
OUTPUT=USB
BACKUP=NETFS
BACKUP_URL="usb:///dev/disk/by-label/REAR-000"
Run rear -v mkbackup to create the rescue media including the archive of the Operating System.
Rescue system
Relax-and-Recover will not automatically add itself to the Grub bootloader.
It copies itself to your /boot folder.
To enable this, add
GRUB_RESCUE=1
to your local configuration.
The entry in the bootloader is password protected. The default password is REAR.
Change it in your own local.conf
GRUB_RESCUE_PASSWORD="SECRET"
Storing on a central NFS server
The most straightforward way to store your DR images is using a central NFS server. The configuration below will store both a backup and the rescue CD in a directory on the share.
OUTPUT=ISO
BACKUP=NETFS
BACKUP_URL="nfs://192.168.122.1/nfs/rear/"
Backup integration
Relax-and-Recover integrates with various backup solutions. Your backup software takes care of backing up all system files, Relax-and-Recover recreates the filesystems and starts the file restore.
Currently Bacula, Bareos, SEP Sesam, HP DataProtector, CommVault Galaxy, Symantec NetBackup, EMC NetWorker (Legato), FDR/Upstream, and IBM Tivoli Storage Manager are supported.
The following /etc/rear/local.conf uses a USB stick for the rescue system and Bacula for backups. Multiple
systems can use the USB stick since the size of the rescue system is probably
less than 40M. It relies on your Bacula infrastructure to restore all files.
BACKUP=BACULA
OUTPUT=USB
OUTPUT_URL="usb:///dev/disk/by-label/REAR-000"
Monitoring integration
Relax-and-Recover integrates with your monitoring. The rear checklayout
command will tell you if the most recent rescue environment deviates from
your storage configuration (e.g. LVM changes, filesystem resized, …)
In good Unix tradition rear checklayout returns 0 if your system is in
sync with your rescue image. A return code of 1 should lead to a red
light in your monitoring screen because a new rescue image is needed. Create
a rescue image and the next time rear checklayout runs, it will return
0 again, and your monitoring will switch to green.
You can also automate the creation of rescue images by adding a cron job for
/usr/sbin/rear checklayout || /usr/sbin/rear mkrescue. And make sure the
OUTPUT_URL points to a central location for storing your rescue images.
By default, a rear installation via a package manager will automatically install
a cron entry - see:
# cat /etc/cron.d/rear
30 1 * * * root /usr/sbin/rear checklayout || /usr/sbin/rear mkrescue
Furthermore, rear will write an exit code to the /var/log/messages file which
you could use to search via an integrated monitoring system (search for the rear keyword).