[ale] has anyone successfully used RSYNC to....

Wolf Halton wolf.halton at gmail.com
Sun Mar 4 16:39:28 EST 2012


Replacing the booted os with an archived copy may also replace /proc.
Though  there may be a way  to avoid that.

http://sourcefreedom.com
On Mar 4, 2012 1:48 PM, "Courtney Thomas" <courtneycthomas at bellsouth.net>
wrote:

> On 03/03/12 15:03, Wolf Halton wrote:
> > On Fri, Mar 2, 2012 at 2:23 PM, Ed Cashin<ecashin at noserose.net>  wrote:
> >> I've done that, but more often, "NEWdrive" is bigger than "HD1" and
> >> "HD2".  I don't have the exact commands handy, but I can describe
> >> them, and whatever anybody tells you about this, make sure you
> >> actually do the procedure you choose *before* you're forced to.
> >> There's inevitably some learning and tweaking, even if you get recipes
> >> from other people.
> >>
> >> So in general, for rsync, I used "-a" plus the option that preserves
> >> sparse files ("-S") and the one ("-H") that preserves hard links, and
> >> often the one ("-c") that uses checksums to ensure data integrity.  Of
> >> course, because rsync works over ssh, it's easiest to keep HD2 in a
> >> separate machine, so that you can rsync over the network.  I use "-x"
> >> to stay on one filesystem instead of going into stuff like /proc.
> >>
> >> Some UNTESTED illustrative example commands from memory are below,
> >> assuming the only real filesystems on the localhost are / and /home.
> >>
> >>   rsync -avSHx / otherhost:/backup-of-hd1
> >>   rsync -avSHx /home/ otherhost:/backup-of-hd1/home
> >>
> >> The most tricky thing about rsync is probably that trailing slash in
> >> the second command.  It means "the contents of".  Without it, rsync
> >> would make a new directory called "home" inside /backup-of-hd1/home on
> >> otherhost.
> >>
> >> For the boot sector, I would copy it to a local file before the rsync
> >> with dd.  But I no longer think that's as good as getting very
> >> comfortable with the installation of a boot loader like grub or lilo.
> >> There's rarely information in the boot sector that cannot be replaced
> >> with something just as good when you're moving onto NEWdrive.  Most of
> >> the time you can live boot a CD and run grub or something to install
> >> the boot loader in the MBR of NEWdrive.
> >>
> >> For the partition table, I used to use sfdisk to dump the partition
> >> info to a format that sfdisk can read to recreate the same
> >> partitioning scheme.  Now I don't think that's necessary either,
> >> because if you're doing a high-level file-based backup like rsync
> >> does, you can just partition NEWdrive however you want, and it's
> >> probably going to be bigger anyway, so good.  And maybe you've learned
> >> something and NEWdrive will have a better partitioning scheme than HD1
> >> did.
> >>
> >> For formatting, I think you mean filesystem creation.  In that case,
> >> again, maybe there's a better choice for the filesystem on NEWdrive
> >> than the one you were using on HD1, so it depends.  Because the backup
> >> is at the file level, you can choose whichever filesystem is best for
> >> your needs.  For example, maybe you have 3 partitions on MYNEWDRIVE
> >> and want ext3, so you could do something like "mkfs -t ext3
> >> /dev/MYNEWDRIVE1" and "mkswap /dev/MYNEWDRIVE2" and "mkfs -t ext3
> >> /dev/MYNEWDRIVE3".
> >>
> >> After that, mount that new filesystem use the same rsync options to
> >> copy the files from the mounted filesystem of HD2 to the new
> >> filesystem on NEWdrive.  Something like this is what you'd do on
> >> "otherhost" after those filesystem creation commands:
> >>
> >>   mkdir /mnt/NEWdrive
> >>   mount /dev/MYNEWDRIVE1 /mnt/NEWdrive
> >>   mount /dev/MYNEWDRIVE3 /mnt/NEWdrive/home
> >>   rsync -avSHx --progress /backup-of-hd1/ /mnt/NEWdrive
> >>   vi /mnt/NEWdrive/etc/fstab  # if you've changed the partitioning
> >> scheme or filesystems
> >>
> >> These commands are pretty darn close, but they're untested and
> >> provided without warranty.  If anyone sees errors, please chime in.
> >>
> >> OP, please practice using them inside virtual machines or something
> >> until you're as comfortable as anyone else if you intend to do this
> >> when other people are counting on it working successfully.
> >>
> >> On Fri, Mar 2, 2012 at 1:38 PM, Courtney Thomas
> >> <courtneycthomas at bellsouth.net>  wrote:
> >>> ...(1) back up all their filesystems from HD1 to an archive hard drive
> HD2,
> >>>
> >>> (2) then replaced HD1 with a NEWdrive which was partitioned, labeled
> and
> >>> formatted exactly duplicating the replaced HD1, and then
> >>>
> >>> (3) RSYNCed the archived files on HD2 to the NEWdrive, with the result
> that:
> >>>
> >>> the NEWdrive was not only without fault, but that the previous
> >>> functionality
> >>> of HD1 was exactly duplicated ?
> >>>
> >>> If yes to all 3, would anyone care to share
> >>>
> >>> (1) the RSYNC backup command for HD1 ->  HD2
> >>> (2) their partition, label and format commands for NEWdrive
> >>> (3) the RSYNC restore command for HD2 ->  NEWdrive
> >>>
> >>> This is obviously of overwhelming importance to all and if anyone can
> >>> point to a
> >>> reliable source, or provide it outright themself, for the above sought
> >>> command
> >>> summary, my gratitude would be boundless  :-)
> >>>
> >>> I am aware that rsync, fdisk, e2label and mkfs are all documented
> commands,
> >>> but a successful usage, as herein outlined, is, at least in my case,
> >>> frustrating
> >>> days away of trial and error, having already wasting such time in
> >>> pursuit of such
> >>> an outcome using 'dump'.
> >>>
> >>> Sincerely,
> >>>
> >>> Courtney
> >>> _______________________________________________
> >>> Ale mailing list
> >>> Ale at ale.org
> >>> http://mail.ale.org/mailman/listinfo/ale
> >>> See JOBS, ANNOUNCE and SCHOOLS lists at
> >>> http://mail.ale.org/mailman/listinfo
> >>
> >>
> >> --
> >>    Ed Cashin<ecashin at noserose.net>
> >>    http://noserose.net/e/
> >>    http://www.coraid.com/
> >>
> >> _______________________________________________
> >> Ale mailing list
> >> Ale at ale.org
> >> http://mail.ale.org/mailman/listinfo/ale
> >> See JOBS, ANNOUNCE and SCHOOLS lists at
> >> http://mail.ale.org/mailman/listinfo
> > I am using rsync to back up zipped copies of configs and whatever else
> > is needed.  This is not a 1:1 of the whole originating disc
> > partitions, as you say you want - but just the important pieces.
> > Presuming the original drive doesn't fail, but only some piece of the
> > puzzle failed, it is still a manual task to recover the piece you
> > need.  My thinking is that if the original drive fails, I have either
> > ZRAID or a system snapshot to return me to the original OS state, and
> > the only thing I am missing is the recent data.
> >
> > tar xzf thearchive.tar.gz
> > rsync -avz the-directory-you-need  root at yourserver.com:
> /path-towhere-it-goes/
> >
> > This is one of the most common errors with rsync as well, in that it
> > is a basic reversal of the original rsync command. B ->  A rather than
> > A ->  B
> > If you are going to be running your rsync from a 3rd machine, as you
> > would have to be doing if you are replacing whole disc-images, I
> > think, you would have full paths at both ends of your command.
> >
> > Ed ++
> > Always test major file-moving on VMs before you trust the process on
> > your production machines.
> >
> > Wolf
> >
> Wolf,
>
> Thank you for your response.
>
> Having not used rsync, why are 3 machines necessary to make whole disk
> copies ?
>
> Why can't an unused disk on the syncing machine be sync'd with the
> desired disk, wherever it's located, including on the syncing machine ?
>
> Cordially,
>
> Courtney
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>
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