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Relax-and-recover (rear) diksrestore script
Best kept secret of recovering with rear is the creation of the diskrestore.sh on the fly with the input from
/var/lib/rear/layout/disklayout.conf file. On occasion issues are created with questions related of failing
to recreate a disk layout (via cloning) and then the disklayout.conf is posted. We are always puzzled to
recreate the diskrestore.sh script by hand (or at least pieces of it).
Therefore, we thought it would be nice if we wrote a script which re-creates the diskrestore.sh script as we
were busy with doing a rear recover without destroying our disks of course. It is always nice to see what
rear makes of the given disklayout.conf input and see what the corresponding output is (diskrestore.sh).
That way it makes it easier to understand what might be the issue.
The script make_rear_diskrestore_script.sh can be download from the mismas github project of Gratien and does
not require any arguments (yet).
$ ~/projects/mismas/make_rear_diskrestore_script.sh
ERROR: make_rear_diskrestore_script.sh needs ROOT privileges!
$ sudo ~/projects/mismas/make_rear_diskrestore_script.sh
##################################################################################
# Starting make_rear_diskrestore_script.sh to produce layout code script
# (for debugging purposes only)
#
# Log file : /var/log/rear/make_rear_diskrestore_script-20160608-0943.log
# date : Wed Jun 8 09:43:58 CEST 2016
##################################################################################
You can now check the script /var/lib/rear/layout/diskrestore.sh
Do _not_ execute script /var/lib/rear/layout/diskrestore.sh
As you can see from the example above just run the script make_rear_diskrestore_script.sh and let it run. Please note, that the script requires root privileges and of course the input file /var/lib/rear/layout/disklayout.conf. It will complain it not found and explain what needs to be done (running rear savelayout).
The output script (diskrestore.sh) can be reviewed for in-depth analysis by the user, e.g.:
$ sudo ls /var/lib/rear/layout/
config disklayout.conf disklayout.conf.20160608.2703.bak diskrestore.sh.20160608.2703.bak lvm
diskdeps.conf disklayout.conf.20160607.22087.bak diskrestore.sh disktodo.conf
You will notice that the make_rear_diskrestore_script.sh makes use of rear libraries and similates a part of the recover process, that is the reason you see in the /var/lib/rear/layout/ directory the backup files. These may be removed afterwards, including the diskrestore.sh script itself as it will always be recreated by rear itself during a real recovery.
#!/bin/bash
# Script /home/gdha/projects/mismas/make_rear_diskrestore_script.sh produced this /var/lib/rear/layout/diskrestore.sh file
# It is meant as debugging aid - do not run it or edit it
# Gratien D'haese - gratien . dhaese @ gmail . com
# Copyright GPLv3
#
############################################################
#
echo "Script /home/gdha/projects/mismas/make_rear_diskrestore_script.sh produced /var/lib/rear/layout/diskrestore.sh file"
echo "It is not meant to be executed - just to review the code"
echo "which recreates your disk layout (for debugging reasons)"
echo
echo "Force exit..."
exit 1
############################################################
############################################################
# Script /var/lib/rear/layout/diskrestore.sh starts below
############################################################
############################################################
#!/bin/bash
LogPrint "Start system layout restoration."
mkdir -p /mnt/local
if create_component "vgchange" "rear" ; then
lvm vgchange -a n >&8
component_created "vgchange" "rear"
fi
Above you see only a small part of a real example of the output and as you can see I protected you from accidental running the script as root and wiping out your disk.
The output is meant for debugging purposes only (so you can see what a recover would execute to recreate your boot disk layout). Or, in case you are completely lost you can open an issue. But, if you expect an answer (on the diskrestore output) a rear subscription, rear support contract or donation is required.
Happy coding - Gratien
References:
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