Re: Equivalencing usernames/ids across computers

[Camaleón <noelamac@gmail.com>]

On Fri, 14 Oct 2011 17:16:39 +0200, Tony van der Hoff wrote:

> On 14/10/11 16:22, Camaleón wrote:
>> On Fri, 14 Oct 2011 13:34:20 +0200, Tony van der Hoff wrote:
>>
>> (...)
>>
>>> So, apart from reallocating user names/numbers at this late stage,
>>> what dou you recommend using to map across the various systems without
>>> my having to think too hard about it?
>>
>> What archiving tool are you using to make the backups?
>>
> rsync
> 
>> "Tar" allows setting the username and group for the copied data so
>> could create a dummy user/group (backup/backup) with a differenet
>> UID/GID to be in charge of all of the backup data between the computers
>> and then pass that information along with the rutine you use (rsync,
>> tar...) by means of, for example, "tar --user backup --group backup
>> ...".
>>
>> On the target system(s) -the one(s) that will contain(s) the backup
>> data- create different folders to differentiate the source
>> ("/backup/laptop", "/ backup/server", "/backup/vps"...).
>>
> We seem to be misunderstanding one another; sorry if I wasn't clear. I
> do indeed have different directories (Isn't "folder" a windowism?) 

I use either, folder and directory, for both environments. When speaking 
to newbies I tend to use "folder" because they seem to understand the 
concept better.

> for each backup, but the files are straight copies, so that I can use
> them equivalently, whichever machine I'm on.
> 
> Rsync does preserve the UID/GIDs correctly, but when I do an ls -l
> /backup/laptop, the user name is shown in accordance with the UID on the
> VPS.

Right, and I guess you want to prevent that but using a dummy account 
does not fit in your backing up plans.
 
(...)

> What I was really hoping to find was some sort of mapping facility that
> changes UIDs originating from, say, laptop from 1001 to 1003, etc.

Then you can add a routine to be run after each rsync round that changes 
the UID/GID (chown) of the backed files depending on where the files are 
located.

Greetings,

-- 
Camaleón