[mdlug] Transfering /home with scp

[Aaron Kulkis]

Robert Meier wrote:
> Peter,
> 
>> I'm finally at the point of transferring all my files to my new notebook.
> 
> I suggest using rsync(1).
> 
> I periodically burn a backup of my /home to cd, as routine.
> 
>> ... Can I simply use scp to copy the entire /home?
> 
> You can subject to some limits:
>     1. Normal users, each have there own directory under /home.
>        Consequently, if you have more than one user,
>        each directory in home will have its own user and group.
>        IIRC, scp will throw out this information.
>        IIRC, tar will record owner information only for files it can read.
>        IIRC, tar will write owner information only if run as root.
>        IIRC, rsync preserves owner information in "archive" mode if able.
>     2. Hard links are limited to a filesystem, and cannot be copied without
>        tools not commonly supported.
>        Consequently, if you have anything dependent on hard links,
>        you'll have to relink those by hand.
>        rsync -H will preserve hard-links where possible,
>        but may take a loooong time.
>        (If you don't know of anything dependent on hard links,
>         then you probably don't have anything dependent on hard links.)
>     3. unix knows users and groups by uid, and gid (integers) mapped
>        for human use to names.
>        Consequently, unless your /etc/passwd and /etc/group files map
>        the same names to the same uids and gids, expect the
>        human-readable names to change.
> 
>> Or are there files in /home that would be
>> specific to the hardware/operating system it's on?
> 
> IMHO, there shouldn't be, but some packages have unnecessary dependencies.
> 
>> Would tar be a better, quicker option?
> 
> If you handle the uid/gid maps manually,
> the tar suggestion would seem the simplest.
>> # cd /home
>> # tar cpf - * | ssh -l root target_host '(cd /home; tar xpf - )'
> 
> The encryption overhead of ssh, is probably less than 50% and
> IMHO well worth the time saved avoiding potential network issues.
> 

It's much simpler to simply connect the the two computers
to a hub which is not connected to anything else, or to
use a cross-over cable between the two.

Then the two machines are physically isolated from the rest
of the world, and no encryption is needed.