Backup failure

[Petter Adsen]

On Sun, 27 Sep 2015 11:16:10 +0200
<silver.bullet at zoho.com> wrote:

> On Sun, 27 Sep 2015 08:34:48 +0200, Petter Adsen wrote:
> >I would probably format the USB stick with a file system that supports
> >all the regular Linux attributes, such as ext4
> 
> Usually I backup to tar archives using compression, but indeed tar
> seems not to preserve attributes.

<snip>

> I anyway prefer tar archives, since backups of complete install become
> much smaller. The tar.gz backups of my around 40 GiB Arch install become
> an archive with a size from around 20 GiB. Something as the immutable
> bit is seldom used. An archive preserves permissions, so it doesn't
> matter if the archive is written to e.g. FAT... or e.g. EXT4, assumed
> attributes shouldn't be important.

Yes, but making incremental backups with tarballs becomes more complex.
If you are backing up to a remote server on the other side of a slow
link you don't want to move the entire 20G archive each and every time,
you only want to copy the things that have changed.

> After restoring complete installs from a backup, I never noticed
> missing functionality of attributes.
> 
> What packages install files that need attributes, that aren't preserved
> by a tar archive? After restoring data files that should have an
> attribute set, I would manually set the attribute. It would be possible
> to backup a list of all attributes to a tar archive and to restore them
> by a script, after restoring the files.

Mea culpa, I actually meant "permissions", not "attributes". Newer
versions of backintime actually store permissions in a separate file,
but you still can't use file systems that doesn't support hard links if
you want to avoid wasting space.

Attributes are mostly interesting if you use SELinux, AFAIK, or for
things like disabling CoW for certain files on btrfs.

Petter

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