What is safe to exclude for a full system backup?

I'm looking for a list which paths/files are safe to exclude for a full system/home backup.

Considering that I have a list of installed packages.

• /home/*/.thumbnails
• /home/*/.cache
• /home/*/.mozilla/firefox/*.default/Cache
• /home/*/.mozilla/firefox/*.default/OfflineCache
• /home/*/.local/share/Trash

• /home/*/.gvfs/

• /tmp/

• /var/tmp/
• not real folders but can cause severe problems when 'restoring'
  • /dev
  • /proc
  • /sys

What about...

• /var/ in general?
• /var/backups/ - can get quite large
• /var/log/ - does not require much space and can help for later comparison
• /lost+found/

Solution 1:

When I rsync my system to a backup partition, I exclude these:

--exclude=/dev/* \
--exclude=/home/*/.gvfs \
--exclude=/home/*/.mozilla/firefox/*/Cache \
--exclude=/home/*/.cache/chromium \
--exclude=/home/*/.thumbnails \
--exclude=/media/* \
--exclude=/mnt/* \
--exclude=/proc/* \
--exclude=/sys/* \
--exclude=/tmp/* \
--exclude=/home/*/.local/share/Trash \
--exclude=/etc/fstab \
--exclude=/var/run/* \
--exclude=/var/lock/* \
--exclude=/lib/modules/*/volatile/.mounted \
--exclude=/var/cache/apt/archives/* \

This way I am able to boot into the backup partition the same way I can boot to the original one.

So to sum up, I would suggest

• not excluding /{dev,proc,media,...} themselves, just their contents

• excluding /var/{run,lock}, and especially the big /var/cache/apt/archives/

Solution 2:

I'll recomend to exclude all /usr (except fort /usr/local/) and have a backup of dpkg --get-selections

In my opinion a Full backup isn't really usefull. I rather prefer backup data and preferences and then restore packages from the official repositories.

But is my preference...

/usr contains mainly static binary content from distribution packages. Reinstalling a package will restore /usr contents. Also /bin and /sbin contains binaries from distribution packages.

/usr/local contains manually installed packages (out of distribuition packages). so this is worth to backup.

Solution 3:

I also read all of the answers and all the other related questions when I was configuring my full system backup.

My 2 cents would be not to exclude anything but only when you are doing a full system backup of an offline system.

Let me elaborate now: If you backing up the system from within itself, then you may exclude some directories as others have mentioned but this is not a good way in my opinion as it can introduce some bugs later on when restoring the system. For example, if you exclude /tmp directory, then after restoring it, /tmp won't be there and system will create one and this can have stuck login screens due to chmod & chown issues on /tmp. Also not backing up ~/.cache directory can result in breaking up database cache of Ubuntu Software Centre.

What I do is use a live CD and use LuckyBackup and backup the entire system without omitting anything. Now when restoring, I chose 'delete files not present in the source'. This way you will have an entire system snapshot restored exactly to the state when you created the backup (kinda like snapshotting a VM).