Re: [gentoo-user] How to build a time machine on Gentoo

[Nganon <nganon+gentoo@gmail.com>]

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On 16 August 2010 03:15, Alex Schuster <wonko@wonkology.org> wrote:

> Nganon <nganon+gentoo@gmail.com <nganon%2Bgentoo@gmail.com>> writes:
>
> > Hello all,
> >
> > My first post on the list. I thought I would start with something
> > that I started
> > to think of as 'essential' after losing 90GB of data. Now I have two
> > main questions in mind: what to and how to back up on gentoo most
> > efficiently.
> >
> > 1. Apart from users' home directories and the followings, what should
> > be backed
> > up on a gentoo machine?
> > /etc/portage/
> > /root
> > /var/lib/portage
> > ...?
>
> Wouldn't it be easier to just backup the whole / directory?
> Excluding /home, /usr/portage and /var/tmp/portage?
>
> Yes but that would not solve my huge backup file problem, would it?


>  > 2. Erm..okay, I am gonna say, what magic I want and then ask your way.
> > I first started making gzipped tar balls as follows:
> >
> > tar czpf /media/backups/userA-`date +%Y.%m.%d`.tgz -X
> > userA-excludelist /etc
> >
> > But these can get huge especially for home dirs. I also want safe dvd
> > copies.
> > Though I can find enough space on the external drives, I don't trust
> > them any more. See above..sigh..(No I recovered about one third of it
> > with testdisk/photorec
> > which names them as file000001 file00002.. and half them are zero
> > sized.. which
> > quite justifies my agony)
>
> Okay, but I don't trust DVDs. Although DVD-RAM is quite safe I heard.
> But external disks are flexible, offer more space, and if you want more
> security, just use yet another drive, so you are safe even if your main
> drive and a backup drive fails.
>
> I did not give a thought to DVD-RAM before. Will give it a try. Thanks.

I suggest you have a look at rdiff-backup. It gives you a 1:1 copy of
> the source directory, but also does incremental backups, which are
> stored (in compressed form) in an additional folder in the destination
> directory. I would use this at least for things like /etc, where I
> sometimes might want to retrieve an old version of a file. Similar to
> your approach with big tar files and small ones containing the
> increments.
>
> I just emerged and tried it. Seems like incremental backups was what I
was looking for. But from what I see, it is mirroring the src to dist and
storing the metadata/stats of increments as archived. Maybe there is an
option to archive increments along side their metadata as well. I will keep
playing with it.

I use a script for my backups, which I mentioned here on 2010-05-07,
> subject 'Snackup'. It optionally creates LVM snapshots so I can make
> backups from the running system, even if the source directory is
> altered during the backup. This works on LVM only, though, and also
> allows the volume to be LUKS-encrypted. It does backups by rdiff-backup,
> rsync, cp, tar or dd. It may be overkill when not using the LVM
> features, but still I suggest to use some script for backups, so one
> does not always have to remember the backup commands. When I want to
> update my backup, I enter something like 'snackup boot root home src',
> and the script backs up my boot, root and home partition in the
> background, and creates tar files each directory in /usr/src.
>
> I found the thread and script. I am gonna take a look at it. Once I decide
on
how to backup, I am gonna cron a script for it.


>  > By the way, since I want dvd backups as well, and I want to use +rw
> > dvds so I can overwrite old backup after a while, what is best way of
> > ensuring the integrity and safety of them. Is it a good idea to use
> > truecrypt containers? Or nothing tops signing and encrypting with gpg?
>
> I'd use DVD-RAM. The media is a little more expensive, but AFAIK they
> were made with long-time backups in mind. And access is much easier,
> you just copy the files as to an external drive, no need to burn ISOs.
>
>        Wonko
>
>
Thanks for the advises.

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