[olug] To RAID or not to RAID

[Dan Linder]

And to follow up with my rsync backup discussion, I found the "rsnapshot"
which appears to be a fully fleshed out implementation of the multi-state
backups I mentioned in the previous email.

Here's the URL: http://www.rsnapshot.org/

It's also a pre-made package in my Linux Mint system so and it doesn't
appear that old.

Dan

On Mon, Sep 22, 2014 at 8:56 PM, Dan Linder <dan at linder.org> wrote:

> This reminded me of an old script I wrote up to keep a number of copies of
> the data but re-using the files on-disk if the data was the same.
>
> Check out this URL: http://www.mikerubel.org/computers/rsync_snapshots/
>
> But the gist of it is this (from the page):
>
> rm -rf backup.3
> mv backup.2 backup.3
> mv backup.1 backup.2
> cp -al backup.0 backup.1
> rsync -a --delete source_directory/  backup.0/
>
> If the above commands are run once every day, then backup.0, backup.1,
> backup.2, and backup.3 will appear to each be a full backup of
> source_directory/ as it appeared today, yesterday, two days ago, and
> three days ago, respectively--complete, except that permissions and
> ownerships in old snapshots will get their most recent values (thanks to
> J.W. Schultz for pointing this out). In reality, the extra storage will be
> equal to the current size of source_directory/ plus the total size of the
> changes over the last three days--exactly the same space that a full plus
> daily incremental backup with dump or tar would have taken.
>
> BUT, BEFORE YOU IMPLEMENT THIS, PLEASE READ THE UPDATES ON THE URL LISTED
> ABOVE.  THERE ARE SOME CLEANER METHODS TO DO THIS that will preserve the
> ownership and permissions, and optimize disk usage after a number of backup
> rotations.  (I'm sure someone has a better script that's up-to-date...)
>
> I did experiment with using the Win32 version of rsync many years ago, but
> I don't believe it supported the
>
> Dan
>
>
> On Mon, Sep 22, 2014 at 8:32 PM, Obi-Wan <obiwan at jedi.com> wrote:
> >
> > On 09/22/2014 06:19 PM, Lou Duchez wrote:
> >>
> >> Any chance you've got a friend out there on the Internets who would let
> you keep a drive at his place?  For my remote backups, I do a two-step
> process:
> >>
> >> 1)    rsync is a great way to back data up across a network (including
> the Ethernet), especially where only a little data changes from one backup
> session to the next.  So let's say I use rsync to back up my data to
> "/backups/current" on the remote system.  Which I then follow with step 2
> ...
> >>
> >> 2)    /bin/cp -al /backups/current /backups/[date]
> >>
> >> What that does is create a dated backup directory, but thanks to the
> magic of the "-l" flag, hard links (not symbolic links) to the files in
> /backups/current are created.  That means I have a logical copy of
> /backups/current that takes up almost no additional drive space because
> it's pointing to the same files on the file system.  Now, if any of those
> files in /backups/current is changed the next time I run rsync, the file in
> /backups/current is unlinked first and a new file is created -- but the
> link to the original in /backups/[date] is left completely untouched.
> >
> >
> > I don't see anything in the rsync man page that indicates it will break
> that hard link when updating an existing file.  How does your setup ensure
> this will happen?  If the link isn't broken, then your old hardlinks will
> get updated along with your current file when rsync changes it.
> >
> > --
> > *Ben "Obi-Wan" Hollingsworth* obiwan at jedi.com <mailto:obiwan at jedi.com>
> www.Jedi.com <http://www.jedi.com>
> > The stuff of earth competes for the allegiance I owe only to the
> > Giver of all good things, so if I stand, let me stand on the
> > promise that You will pull me through. /-- Rich Mullins/
> >
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>
>
>
>
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-- 
***************** ************* *********** ******* ***** *** **
"Quis custodiet ipsos custodes?"
    (Who can watch the watchmen?)
    -- from the Satires of Juvenal
"I do not fear computers, I fear the lack of them."
    -- Isaac Asimov (Author)
** *** ***** ******* *********** ************* *****************