# Ubuntu – Back Up Ubuntu 17.04

backupdual-bootpartitioningrsynctar

I have a dual boot system installed on my pc (Ubuntu 17.04 & Windows 8.1)
and I'd like to back up the Ubuntu partition on external HD.

Some info:

# fdisk -l

Disk /dev/sda: 931,5 GiB, 1000204886016 bytes, 1953525168 sectors
Units: sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 4096 bytes
I/O size (minimum/optimal): 4096 bytes / 4096 bytes
Disklabel type: gpt

Device          Start        End    Sectors   Size Type
/dev/sda1        2048     616447     614400   300M Microsoft basic data
/dev/sda2      616448     819199     202752    99M EFI System
/dev/sda3     1081344 1172967549 1171886206 558,8G Microsoft basic data
/dev/sda4  1172969472 1953523711  780554240 372,2G Linux filesystem


Ok so I've looked around a bit and found a few ways to do this:

A) tar

B) dd

C) rsync

Now, from what I understood:

• "tar" command would basically just compress and copy the directories one wants to back up into a .tgz file which can then be moved to my external HD. It can also be used with bzip2 to compress even more.

• "dd" command creates a .dd image of the wanted partition. So it would make a full back up each time.

• "rsync" command is used for incremental back ups. It basically looks for and saves only the files that have been added or changed since the last back up.

I've never even attempted to do a back up so I've got a lot of questions to ask.

Let's say one has his nice back up file on his external HD and one day decides to restore it for some reason:

1) Can It only be done on the same machine the back up was created?

2) Can It only be done on the same OS the back up was created?

Other questions:

3) Let's say I do a full back up of my Ubuntu partition with tar, can I then use rsync to add the changes and basically update my "backup.tgz" file?

EXAMPLE:

cd /
sudo tar -cvpzf /backup.tgz --exclude=/proc --exclude=/lost+found  --exclude=/backup.tgz --exclude=/mnt --exclude=/sys /


Can I then do:

sudo rsync --delete -av /backup.tgz  /


?

EDIT:

Ok so, I've backed up the / directory with :

sudo tar -cvpzf /Ubuntu_17.04_ROOT_BackUp-date+%d-%m-%Y.tgz --exclude=/proc --exclude=/lost+found --exclude=/Ubuntu_17.04_ROOT_BackUp-date+%d-%m-%Y.tgz --exclude=/mnt --exclude=/sys /


It took a couple hours but my back up file (of 64.3 GB) was created.
This was the terminal output at the end:

tar: /: file changed as we read it
tar: Exiting with failure status due to previous errors


Is this a standard output at the end of a back up with tar or something went really wrong?