Re: backup snapshot

[Diogene Laerce]

Hi Rick,

Le 11/08/2015 19:18, Rick Stevens a écrit :
> On 08/11/2015 09:18 AM, Chris Murphy wrote:
> > On Tue, Aug 11, 2015 at 3:05 AM, Diogene Laerce 
> > wrote:
> > > > https://wiki.archlinux.org/index.php/Full_System_Backup_with_rsync
> > >
> > > Is there a trick I don't see here ? Because if the backup of those
> > > directories
> > > is enough for a full restoration of a system state, this method is
> > > far more
> > > efficient than the others, isn't it ? As one does not need to reboot
> > > and
> > > just have
> > > to make a script or/and a cron job to make his own snapshot.
> >
> > I don't consider a backup and snapshot to be the same thing. Copying
> > (or rsyncing) some directories to another volume is a backup. A
> > snapshot is a deduplicated copy of something at a particular moment in
> > time, on the same volume or storage pool. It's not a backup, in that
> > if the pool implodes both the original and snapshot are lost. A
> > snapshot can be used as a source for a backup, since you can make a
> > snapshot that doesn't change while the backup is happening.
>
> I agree with Chris. Snapshots are ways of restoring data that has been
> perhaps corrupted or deleted or going back in time to some earlier
> point in the filesystems' life. They aren't backups.
>
> Backup philosophies and techniques vary depending on what you need for
> your unique situation. I'm not claiming what I do is the best, but this
> is what works for me:
>
> On the last Friday of a month, I plug in a big ESATA or USB3 drive and
> use it to store the output of Mondo Rescue. I have the backup in the
> form of DVD-sized ISO images I can burn DVDs from and there is a
> recovery DVD you can boot from. That gives me a backup usable to
> restore to bare metal.
>
> Once a week (or more often if there's been significant changes), I use
> a _different_ ESATA or USB3 drive and run an rsync that backs up
> everything except a few things (/proc, /sys, /dev, /media,
> /var/log/journal, various caches, etc.) to a directory on that external
> drive based on the hostname and date I ran the backup. That permits me
> to restore data that's a bit more recent than the MondoRescue stuff.
>
> I'd be happy to share the MondoArchive and rsync scripts if you wish.
> Tweak to suit your needs.

Thank you for the offer.

I'm going to stick with RedoBackup but I'd really like to have a look at
your rsync scripts, and maybe at what various caches you think of.

Kind regards,