consistent UIDs across multiple systems.

Rashkae ubuntu at
Mon Oct 19 13:36:39 UTC 2015

On 15-10-18 08:41 PM, Rei Shinozuka wrote:
> my user login on my ubuntu 14.10 system is "shino" and its uid is 
> 1001.  i recently acquired a synology 1815+ NAS and added users to the 
> system.  on the synology, the uid for "shino" is 1026, which is 
> visible in the NAS's /etc/passwd.  the problem arises when mounting 
> CIFS on a PC (win8.1) using the login "shino"; files it creates are 
> UID 1026 and it can't read/write existing directories created with UID 
> 1001.
> I'm looking for recommendations for the best way to maintain a uniform 
> name/uid mapping across systems (including the NAS).  i don't mind 
> manually changing multiple systems, there are a small number of users 
> (basically my family) and that's not likely to change anytime soon.
> thanks,
> -rei

Are you using NFS between the NAS and Linux, and CIFS between Windows 
and the NAS?  synchronizing the UID's would probably make it work, but 
for simplicity, I would suggest simply mounting the share point with 
CIFS on Linux as well.  (you will have to change the ownership of all 
the existing files/directories on the NAS for this to work, however.)

I'm not an expert on this subject, but I think there can be issues with 
sharing the same files with both CIFS and NFS.  In particular, I expect 
the NFS clients will be able to walk all over the CIFS file locks, which 
the Windows clients will be expecting to be honoured.

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