[mythtv-users] NFS mounts permissions

Mike Perkins mikep at randomtraveller.org.uk
Sat Sep 8 17:12:35 UTC 2007

Daniel Kristjansson wrote:
> Unix doesn't use the name of the account or group, it uses the 
> user and group numbers. So they must be the same across all your
> computers:
> [danielk at prude ~]$ grep mythtv /etc/passwd
> mythtv:x:105:105::/home/mythtv:/bin/bash
> [danielk at prude ~]$ grep mythtv /etc/group
> mythtv:x:1000:
> [danielk at cuy ~]$ grep mythtv /etc/passwd
> mythtv:x:105:105::/home/mythtv:/bin/bash
> [danielk at cuy ~]$ grep mythtv /etc/group
> mythtv:x:1000:
> If they don't agree you can't authenticate. Also if you run the
> backend as root you generally can't write to NFS shares because
> most NFS implementations only give the root account guest access
> if they give it any access at all.
> You can edit the numbers in the passwd and group files on one
> computer so they agree with the other one, but make sure you
> chown mythtv:mythtv -R /directory/that/should/be/owned/by/mythtv
> on all directories used by the mythtv account afterward, this
> includes /home/mythtv and all your local recording directories
> and any directories used by any plugin.
> FYI In large unix installations there is usually an account
> server such as yp, so this doesn't happen. But desktop Linux
> distro's don't use such things by default.
FYI I learned the hard way that Mandr[ake,iva] allocates some of it's account 
numbers on the fly on installing the appropriate application - and that includes 
mythtv. I could see the shares, but the user/group ids were "strange". After 
much bodging around I bit the bullet and reinstalled (not for that reason 
alone), setting mythtv to be a manually numbered user (a normal user). Doesn't 
seem to have done any harm (so far). May be a consideration for other distros.

I notice YP/NIS mentioned above. To try to get round some of these problems I 
have been considering LDAP. Anybody with experience in a mixed Linux/Windows 
installation who would be willing to pass on tips - it would be appreciated.

Mike Perkins

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