backups using rsync

Ronald F. Guilmette rfg at
Mon Mar 4 11:35:36 UTC 2013

As a result of this past Black Friday weekend, I now enjoy a true abundance
of disk space, for the first time in my life.

I wanna make a full backup, on a weekly basis, of my main system's shiny
new 1TB drive onto another 1TB drive that I also picked up cheap back on
Black Friday.

I've been planning to set this up for some long time now, but I've only
gotten 'round to working on it now.

Now, unfortunately, I have just been bitten by the evil... and apparently
widely known (except to me)... ``You can't use dump(8) to dump a journaled
filesystem with soft updates'' bug-a-boo.

Sigh.  The best laid plans of mice and men...

I _had_ planned on using dump/restore and making backups from live mounted
filesystems while the system was running.  But I really don't want to have
to take the system down to single-user mode every week for a few hours while
I'm making my disk-to-disk backup.  So now I'm looking at doing the backups
using rsync.

I see that rsync can nowadays properly cope with all sorts of oddities,
like fer instance device files, hard-linked files, ACLs, file attributes,
and all sorts of other unusual but important filesystem thingies.  That's
good news, but I still have to ask the obvious question:

If I use all of the following rsync options...  -a,-H,-A, -X, and -S ....
when trying to make my backups, and if I do whatever additional fiddling
is necessary to insure that I separately copy over the MBR and boot loader
also to my backup drive, then is there any reason that, in the event of
a sudden meteor shower that takes out my primary disk drive while leaving
my backup drive intact, I can't just unplug my old primary drive, plug in
my (rsync-created) backup drive, reboot and be back in the sadddle again,
almost immediately, and with -zero- problems?


P.S.  My apologies if I've already asked this exact same question here
before.  I'm getting a sense of deja vu... or else a feeling that I am
often running around in circles, chasing my own tail.

P.P.S.  Before anyone asks, no I really _do not_ want to just use RAID
as my one and only backup strategy.  RAID is swell if your only problem
is hardware failures.  As far as I know however it will not save your
bacon in the event of a fumble fingers "rm -rf *" moment.  Only frequent
and routine actual backups can do that.

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