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[ale] backup/restore mail from USB external drive



On Tue, Feb 11, 2014 at 6:15 PM, John Heim <john at johnheim.com> wrote:

>
> So we have a failing RAID5 array on our mail server.  I rsynced the mail
> to an external USB drive (formatted ext3, thanks) It looks like I am going
> to have to completely re-install. I want the outage to be as short as
> possible. I am thinking this:
>
> 1. Repeat the rsync with the system up so as to not inconvenience users.
> There will be a lot of "file changed as we read it" kind of errors.
> 2. Shutdown the mail programs.
> 3. Run rsync again.  This time there shouldn't be any errors.
> 4. Install the new disks, reformat, re-install.
> 5. Copy the mail files back.
>
> Any suggestions as to the most efficient way to do step #5? There would be
> no point in using rsync because the time it spends checking for changed
> files would be wasted.
>
> John Heim
>


'rsync' is still a good option to copy files back.  It does not do a full
check of files unless they already exist on the destination side, and even
then it checks the date and filesize before doing a full checksum.  If you
use the options, you can preserve timestamps, view progress, and easily
stop/restart the copy if needed.  I'd use these options: -av --progress
--partial.  When copying between local disks, it's just a version of 'cp'
that gives you a lot more options.  Also, I'd recommend running this inside
of a 'screen' or 'tmux' session so you can detach and leave it running,
and/or protect against the session getting dropped from the network.

As far as step 5 goes, do you have enough physical space to add the new
drives next to the old ones?  Then you could make a partition for the user
data and stage it directly on the new drives.

Incidentally, the point of a RAID is to be able to replace failing drives
without having to go through this process.  Is there any reason why you
can't just replace the failing drive and rebuild the existing RAID to it?


P.S. RAID is not a backup and you should always have some kind of backup
job running to external media regardless of the health of the RAID.


? Brian Mathis



? Brian Mathis


On Tue, Feb 11, 2014 at 6:15 PM, John Heim <john at johnheim.com> wrote:

>
> So we have a failing RAID5 array on our mail server.  I rsynced the mail
> to an external USB drive (formatted ext3, thanks) It looks like I am going
> to have to completely re-install. I want the outage to be as short as
> possible. I am thinking this:
>
> 1. Repeat the rsync with the system up so as to not inconvenience users.
> There will be a lot of "file changed as we read it" kind of errors.
> 2. Shutdown the mail programs.
> 3. Run rsync again.  This time there shouldn't be any errors.
> 4. Install the new disks, reformat, re-install.
> 5. Copy the mail files back.
>
> Any suggestions as to the most efficient way to do step #5? There would be
> no point in using rsync because the time it spends checking for changed
> files would be wasted.
>
>
>
> an
>
> --
> John Heim
> email: john at johnheim.com  skype: john.g.heim
>
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