ID Numbering in Group and Passwd
Robin Laing
Robin.Laing at drdc-rddc.gc.ca
Fri Nov 25 21:18:49 UTC 2005
James Wilkinson wrote:
> Robin Laing wrote:
>
>>Using the reverse method for groups would even remove the necessity to
>>set GID_MIN unless there are 40,000 unique groups which I find really
>>impossible.
>
>
> With the Red Hat standard "user private groups" (one group per user),
> all you need is 40000 users.
>
> In a big university or company, that's not impossible.
>
> http://www.redhat.com/docs/manuals/linux/RHL-7.2-Manual/ref-guide/s1-users-groups-private-groups.html
>
> James.
>
I wasn't talking about user groups. I was talking about groups that
don't have specific users. In my case it is shared groups for family
files, groups for shared multimedia files that I don't want my kids to
view etc.
To explain further.
Users start at 500 as they do now. If I want to add a group such as
mpaa-R for R rated DVD's that I stored on my system, they would start
at 60,000 if I had GID_MAX set to 60,000.
Lets say I have 12 users and 11 extra groups. This means that the
USER GID's are 500-512 The extra groups are 59,989-60,000.
This means that there could be upto 59,489 total users using RH's
UID=GID concept before a collision unless more groups were added. No
real need to manually select GID's or even to change limits if the
defaults are set properly.
All UID/GID combos are still in order if the defaults work as expected.
Does this clear up some of the mud now? :)
Robin.
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