[mythtv-users] Rsync test system

[Nicolas Krzywinski]

Hi Daryl,

you aren't over cautious. I _always_ do a full system backup before 
doing a major system upgrade. This allowed me to recover my system a few 
times already, when the upgrade failed. Last time, it was my home 
server, still running Debian Wheezy (!), cause the last upgrade attempt 
completely broke the system.

For my main systems (my home server and my personal system), I 
permanently have a backup system on a second disk, that I resync from 
time to time. Sometimes, I just boot into one of these backup systems to 
check for regressions, just to sort out that I don't remember things 
correctly.

Additionally I have a spare SSD that I use for full system backups for 
systems like e. g. the MythTV backend/frontend.

Over the years, I created a script that helps me doing these system 
backups more faster and less error-prone than me, trying to remember all 
the single steps.

The script does these steps:

1. rsync the different system paths to the new target location, that may 
consist of either one or multiple partition(s)

2. create empty system directories at the target location (I don't know 
if they are created automatically, just wanna be sure everything works)

3. copy the init symlinks from root dir

4. compare the directory sizes of source and target to detect any major 
failures

5. chroot into target directory for running update-grub

6. update of /tar/get/etc/fstab to insert mounts of target partition(s) 
- (!) everything else is commented out (!) - support for swap partition 
missing currently, this has to inserted manually!

Additionally, there are some parameters to control the script. Some 
parameters enables/disables some of the above steps. Other parameters 
can be used to e. g. exclude specific directories or let the script run 
unattended. Finally, there are parameters that adjust how to deal with 
existing backup data at the target location, e. g. fully sync the source 
system to the target location, which possibly means to DELETE target files.

Because of this, the script can be dangerous, if configured incorrectly!

When using it, do everything with extra care, to not harm your system or 
lose any data! I propose to use it interactively and triple check all 
the paths, the script prints out, prior to starting any actions.

Depending on the system, there may be some error messages when copying 
stuff from / (root), as the different distros have some differencies 
there. I tried to add support for all systems that I had worked with so 
far, but I can guarantee for nothing! ;-)

Good luck,

Nicolas


Am 07.10.2017 um 09:33 schrieb mythtv-users-request at mythtv.org:
> Message: 15
> Date: Fri, 6 Oct 2017 16:12:35 -0400
> From: Peter Bennett<cats22 at comcast.net>
> To:mythtv-users at mythtv.org
> Subject: Re: [mythtv-users] Rsync test system
> Message-ID:<d5e1e31f-0b17-f9db-ba18-48748c086863 at comcast.net>
> Content-Type: text/plain; charset="utf-8"; Format="flowed"
>
>
>
> On 10/06/2017 02:24 PM, Daryl McDonald wrote:
>> Thanks Peter this looks good, as far as copying the system, but I want
>> to end up with a dual boot system so editing the /etc/fstab, to change
>> the first boot drive is probably not for me. After the copy I'm
>> tempted to then run update-grub, is this too easy? I could edit
>> /etc/default/grub to change boot order as required. I want this setup
>> in place for more than just 0.28 to 0.29 Also for all future system
>> and myth upgrades.
>> Its occurring to me that I will have to edit /etc/fstab to auto mount
>> the new partition. Am I missing anything else?
>>
>>
> I do use this for setting up a multi-boot system. Each partition is a
> complete copy so each partition has its own /etc/fstab which must be
> edited to use the correct root partition (i.e. itself). After making the
> copy and editing that fstab you should be able to boot into your
> original system and then run sudo update-grub.
>
> If you want to switch your default boot partition you should reinstall
> grub into the new default partition.

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