168 lines
5.3 KiB
Text
168 lines
5.3 KiB
Text
ccollect - Restoring backups
|
|
============================
|
|
Nico Schottelius <nico-ccollect__@__schottelius.org>
|
|
0.1, for all ccollect version, Initial Version from 2008-07-04
|
|
:Author Initials: NS
|
|
|
|
|
|
Having backups is half the way to success on a failure.
|
|
Knowing how to restore the systems is the other half.
|
|
|
|
|
|
Introduction
|
|
------------
|
|
You made your backup and now you want to restore your
|
|
data. If you backuped only parts of a computer and need
|
|
only to restore them, it is pretty easy to achieve.
|
|
Restoring a whole system is a little bit more
|
|
difficult and needs some knowledge of the operating system.
|
|
|
|
|
|
Restoring parts of a system
|
|
~~~~~~~~~~~~~~~~~~~~~~~~~~~
|
|
Log into your backupserver. Change into the
|
|
backup directory you want to restore from.
|
|
Do `rsync -av './files/to/be/recovered/' 'sourcehost:/files/to/be/recovered/'.
|
|
|
|
Restoring a complete system (general)
|
|
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
|
|
Boot the system to be rescued from a media that contains low level tools
|
|
for your OS (like partitioning, formatting) and the necessary tools
|
|
(ssh, tar or rsync).
|
|
Use
|
|
- create the necessary partition table (or however it is called
|
|
|
|
Get a live-cd, that ships with
|
|
- rsync / tar
|
|
- ssh (d) -> from backupserver
|
|
- support for the filesystems
|
|
|
|
Restoring a complete FreeBSD system
|
|
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
|
|
Get a FreeBSD-live-cd (I used the FreeBSD 7.0 live CD,
|
|
but FreeSBIE (http://www.freesbie.org/),
|
|
Frenzy (http://frenzy.org.ua/en/) or the
|
|
FreeBSD LiveCD (http://livecd.sourceforge.net/)
|
|
may also be helpful. The following way uses the FreeBSD 7.0
|
|
live cd.
|
|
|
|
So boot it up, select your language. After that select
|
|
*Custom* then *Partition*. Create the slice like you want
|
|
to have it. Then let the installer write into the MBR,
|
|
select *BootMgr*.
|
|
|
|
After that create the necessary labels, select *Label* and
|
|
make sure "Newfs" flag is set to "Y".
|
|
|
|
Finally, select *Commit* and choose an installation type
|
|
that must fail, because we want the installer only to write
|
|
the partitions and labels, but not to install anything on it.
|
|
|
|
At this point we have created the base for restoring the whole
|
|
system. Move back to the main menu and select *Fixit*, then
|
|
*CDROM/DVD*. This starts a shell on TTY4, which can be reached
|
|
by pressing *ALT+F4*. Then enter the following data:
|
|
|
|
--------------------------------------------------------------------------------
|
|
rootdir=/ccollect
|
|
rootdev=/dev/ad0s1a
|
|
backupserver=192.42.23.5
|
|
|
|
# create destination directory
|
|
mkdir "$rootdir"
|
|
|
|
# mount root; add other mounts if you created more labels
|
|
mount "$rootdev" "$rootdir"
|
|
|
|
# find out which network devices exist
|
|
ifconfig
|
|
|
|
# create the directory, because dhclient needs it
|
|
mkdir /var/db
|
|
|
|
# retrieve an ip address
|
|
dhclient fxp0
|
|
|
|
# test connection
|
|
ssh "$backupserver"
|
|
|
|
# go back
|
|
backupserver% exit
|
|
--------------------------------------------------------------------------------
|
|
|
|
Now we've prepared everything for the real backup. The next problem maybe,
|
|
that we cannot (should not) be able to login as root to the backup server.
|
|
Additionally the system to be restored may not reachable from the backup server,
|
|
because it is behind a firewall or nat.
|
|
Thus I describe a way, that is a little bit more complicated for those, that
|
|
do not have these limitations, but works in both scenarios.
|
|
|
|
I just start netcat on the local machine, pipe its output to tar and put
|
|
both into the background. Then I create a ssh tunnel to the backupserver,
|
|
which is then able to connect to my netcat "directly".
|
|
|
|
--------------------------------------------------------------------------------
|
|
# user to connect to the backupserver
|
|
myuser=nico
|
|
|
|
# our name in the backup
|
|
restorehost=server1
|
|
|
|
# the instance to be used
|
|
backup="weekly.20080718-2327.23053"
|
|
|
|
# Need to setup lo0 first, the livecd did not do it for me
|
|
ifconfig lo0 127.0.0.1 up
|
|
|
|
# change to the destination directory
|
|
cd "$rootdir"
|
|
|
|
# start listener
|
|
( nc -l 127.0.0.1 4242 | tar xvf - ) &
|
|
|
|
# verify that it runs correctly
|
|
sockstat -4l
|
|
|
|
# connect as a normal user to the backupserver
|
|
ssh -R4242:127.0.0.1:4242 "$myuser@$backupserver"
|
|
|
|
# become root
|
|
backupserver% su -
|
|
|
|
# change to the source directory
|
|
backupserver# cd /home/server/backup/$restorehost/$backup
|
|
|
|
# begin the backup
|
|
backup # tar cf - . | nc 127.0.0.1 4242
|
|
|
|
# wait until it finishes, press ctrl-c to kill netcat
|
|
# logoff the backupserver
|
|
backupserver# exit
|
|
backupserver% exit
|
|
--------------------------------------------------------------------------------
|
|
|
|
Now we are just right next to be finished. Still, we have to take care about
|
|
some things:
|
|
|
|
- Do the block devices still have the same names? If not, correct /etc/fstab.
|
|
- Do the network devices still have the same names? If not, correct /etc/rc.conf.
|
|
|
|
If everything is fixed, let us finish the restore:
|
|
|
|
--------------------------------------------------------------------------------
|
|
# cleanly umount it
|
|
umount "$rootdir"
|
|
|
|
# reboot, remove the cd and bootup the restored system
|
|
reboot
|
|
--------------------------------------------------------------------------------
|
|
|
|
Restoring a complete Linux system
|
|
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
|
|
TO BE DONE
|
|
|
|
Future
|
|
------
|
|
I think about automating full system recoveries in the future.
|
|
I think it could be easily done and here are some hints for
|
|
people who would like to implement it.
|