[Burp-users] include vs. filesystem boundaries

[Pascal S. <d-s...@ps...>]

Hi

i am in the process of migrating my backup from a self written rsync 
wrapper to burp. I am having some difficulties wrapping my head around 
how burp works with corssing filesystems and the difference between the 
"include" and "cross_filesystem" config options

for the following let's assume i have a linux installation with these 
mounts:

/dev/sda1 -> /
/dev/sda2 -> /boot

inside my /boot directory i have two sub directories, /boot/grub and 
/boot/test

in my config on the burp client i have set cross_all_filesystems=0

i want to backup only / and /boot/test but nothing else from /boot 
should be backed up

after some playing around, i found the following config to probably be 
the best solution for what i want:

include=/
cross_filesystem=/boot
exclude=/boot
include=/boot/test

here is what else i have tested:

# test 1

include=/
include=/boot/test

-> this does not backup anything in /boot, it just contains the empty 
mountpoint - this was unexpected, coming from rsync, i would have 
expected this to do what i actually wanted :)

# test 2

include=/
cross_filesystem=/boot/test

-> same as above, emtpy /boot in my backup - that was expected as the 
manpage says that cross_filesystem should be given mountpoints of 
fileystems to cross, so no surprise there

# test 3

include=/
include=/boot

-> this backed up the entire boot directory and all its contents, so it 
seems to automatically trigger the cross_filesytsem in the background

# test 4

incldue=/
include=/boot
exclude=/boot
include=/boot/test

-> this resulted in /boot/test and its contents being in the backup 
twice, but other than that nothing else from /boot was in there.. so 
short of creating duplicates this did almost the same as my final solution

so my question is: is my solution above with setting cross_fileystem to 
the mount point, then excluding the mount point and finally including 
what i really want to backup currently the actual way to go or is there 
a more elegant solution to it?

a change i would request to make this more intitive: At least for me (as 
a long time rsync user i have to admit, so i might be biased here) it 
seems a lot more intuitive to use the configuration of my "test 1" to 
achieve what i wanted here. especially since "test 3" showed, that when 
I include a mountpoint it automatically crosses over to that filesystem, 
which I totally agree on doing.

Now if that change was made, and the syntax as used in "test 1" implied 
automatically that crossing into the /boot filesystem was allowed, I  
think there might be no reason to keep the "cross_filesystem" config 
option any longer as it would just be a sort of a limited synonym for 
"include" that only works on mountpoints :) .. frankly i think this 
would make things a lot easier to comprehend

the behavior in "test 4" may be expected for someone who knows the 
internals of burp but from a newbie user point of view this is a bug. I 
see no reason to ever have the same file contained twice i the same backup.


with all that said, thanks for writing, maintaining and most importantly 
sharing burp! it looks like an awesome tool to me :) I have had burp on 
the radar for a while, sort of used it a long time ago to try to backup 
some windows notebooks of friends and family but got lazy on maintaining 
the setup after a while.. now i am "back" moving over from my own rsync 
based backup script due to the ever increasing danger of ransomware 
worms and what they can do to other types of backups. in case you are 
interested in a long(er) read and my thought process that brought me 
over to burp, have a look at 
http://wiki.psuter.ch/doku.php?id=rethinking_my_backup_strategy it 
really shows some areas where burp was ahead of many other solutions 
back when you started developing it.

cheers

Pascal