Making a bootable backup (hard)disk... how?

[Warren Block]

On Fri, 8 Jun 2012, Robert Huff wrote:

>
> Ronald F. Guilmette writes:
>
>>  I got a lot of disks here, so that part is not a problem.  I just
>>  need to make sure that I'm gonna do this the Right Way[tm].
>>  (I've already been making my own ham-fisted disk-to-disk backups
>>  in the past, but I'm sure that the way I have been doing that is
>>  sub-optimal, so I'm here seeking knowledge of how to do this the
>>  Right Way.)
>>
>>  The bottom line is this... I know how to use cpio, and would like
>>  to use it to create a complete and _bootable_ backup of my main
>>  system disk.  (My main system disk has only one BIOS partition,
>>  and that is sub-divided into the usual set of FreeBSD partitions,
>>  you know, /, /dev, /tmp, /usr, /var, /usr/compat/linux/proc, and
>>  /var/named/dev.)
>
> 	As far as I know, the only way guaranteed to preserve metadata
> is dump/restore.  See previous (not necessarily recent) discussion
> (on this list, and possibly in the Handbook) for more information.

The rsync port has a flags option.  I haven't tried it for a full 
backup.  Even if it can copy all filesystem attributes like dump, there 
are still non-filesystem things needed for booting that neither can 
copy, like partition tables and boot blocks.  There might be something 
for a bootable backup in ports, or it could be done with a script using 
gpart.  Set up the disk with GPT labels to make it relocatable, use dump 
to copy everything the first time, fix up a few things like fstab and 
ifconfig_DEFAULT in the same script.

Afterwards, rsync may be enough for fast updates.