Re: [rdiff-backup-users] Safe to mirror backup dir with rsync?

[Alex Samad]

On Wed, Dec 23, 2009 at 04:55:11PM -0800, Engel Sanchez wrote:
> Hi Alex. My understanding could be wrong, but this is the scenario that I'm 
> trying to avoid:
> 
> 1) Machine 1 has the original data and backs it up locally to /backup
> 2) Machine 2 rsyncs /backup to local /backup every day
> 3) Machine 2 is rsyncing /backup, and right then machine 1 dies for good 
> (fire, flood, apocalypse)
> 
> At that point in time, machine 1 is dead and /backup in machine 2 is not a 
> valid rdiff-backup directory, so you can't restore your data from it anymore. 
>  If Machine 2 was instead using rdiff-backup on the original sources, /backup 
> would have an incomplete backup, but previous data would not be lost, so you 
> can restore from it even if it was interrupted.


Very true, another example of different horses for different courses. At
any one time I have 3 rdiff backup repos. 1 local machine, 1 local lan
another machine and 1 different location.

the rsync's are done in sequence, so if the source dies the off site one will 
have a complete backup.


All this does is show how DR / Backups / HA (not all the same) have to
be considered for each case.

A

> 
>  Engel A. Sanchez
> 
> 
> “Do what you love to do and give it your very best. Whether it's business or 
> baseball, or the theater, or any field. If you don't love what you're doing 
> and you can't give it your best, get out of it. Life is too short. You'll be 
> an old man before you know it.”
> 
> 
> http://engelsanchez.net
> 
> 
> 
> ----- Original Message ----
> From: Alex Samad <address@hidden>
> To: address@hidden
> Sent: Wed, December 23, 2009 6:32:37 PM
> Subject: Re: [rdiff-backup-users] Safe to mirror backup dir with rsync?
> 
> On Wed, Dec 23, 2009 at 01:58:30PM -0800, Engel Sanchez wrote:
> > Thank you all for your suggestions!  I'm going to go with the solution of 
> > doing cascaded rdiff-backups both pointing at the source directories and 
> > without rsync and simply spreading the cron jobs to avoid touching the 
> > sources while they are updated (the sources are hot copies of a couple of 
> > databases and a subversion repo).  Using rsync and risking leaving the 
> > remote backup in a bad state didn't seem like a great idea to me. (Say 
> > rsync's connection breaks and original server fails before next backup). At 
> > least rdiff-backup can deal with a partially updated backup if also done by 
> > rdiff-backup.  
> 
> strange for the same reasons I have used rsync - I can capture when it
> fails and restart and it doesn't need to roll back it continues where it
> left off. rdiff-backup has to unroll and then restart so for a 2 hour
> backup that fails in the last 10 min, you will need to do another 2
> hours of backup with rdiff-backup and only 10 min with rsync....
> 
> to stop the corruption problem right now I use semaphores around my
> backup scripts to stop certain things happening at the same time :)
> 
> Alex
> 
> > 
> >  Engel A. Sanchez
> > 
> > 
> > “Do what you love to do and give it your very best. Whether it's business 
> > or baseball, or the theater, or any field. If you don't love what you're 
> > doing and you can't give it your best, get out of it. Life is too short. 
> > You'll be an old man before you know it.”
> > 
> > 
> > http://engelsanchez.net
> > 
> > 
> > 
> > ----- Original Message ----
> > From: Alex Samad <address@hidden>
> > To: address@hidden
> > Sent: Wed, December 23, 2009 4:13:16 PM
> > Subject: Re: [rdiff-backup-users] Safe to mirror backup dir with rsync?
> > 
> > On Wed, Dec 23, 2009 at 12:52:03AM +0100, Cybertinus wrote:
> > > Hello,
> > > 
> > > I'm using rdiff-backup to create the backups of my directories. It all
> > > goes to /backup, which is a external harddrive. Then I'm using rsync to
> > > mirror everything to /backup_sync, which is a second external harddrive.
> > > This one is encrypted and I move it to an external location once a week
> > > (and the disk from the external location then becomes the sync disk ;)
> > > ). I'm using this strategy because when I swap the sync disks, they are
> > > disconnected from my computer for a day. Some data I'm backing up every
> > > hour, so I need a external drive at my computer at all times.
> > > This system is working perfectly for me. The only thing I would
> > > recommend is to prevent running rdiff-backup at the same time as rsync.
> > > To prevent that your mirror is accidentally destroyed, because you would
> > > by rsyncing incomplete rdiff-backup data. I haven't build in this
> > > precaution in my backupscripts yet. For the time being I'm preventing it
> > > from running at the same moment by choosing the correct times in my
> > > cronjobs.
> > 
> > Hi
> > 
> > I am doing something similar.
> > 
> > local machine rdiff-backup to /backup (lvm partition).
> > then a rsync to the local backup server and at the same time a rsync to
> > an offsite location - via adsl.
> > 
> > I do this because my initial rdiff-backup can happen quickly and cause
> > the lest disruption - if the source is on a lvm I can take a snapshot
> > and use that but not all the sources are.
> > 
> > I have come across one problem, if the over adsl takes too long the
> > rdiff-backup destination on the local machine can change thus giving you
> > a non in sync backup offsite.
> > 
> > There is another thread asking for a tool to lock the destination to
> > prevent this
> > 
> > Alex
> > 
> > > 
> > > Cheers,
> > > Cybertinus
> > > 
> > > On 23/12/09 00:03, Gavin wrote:
> > > > Hi Engel,
> > [snip]
> > 
> 

-- 
Boucher's Observation:
        He who blows his own horn always plays the music
        several octaves higher than originally written.

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