User IDs - safe to change?

[Marlou Everson]

I am preparing to install 11.11 on a production system. I have already cold-installed the OS on another system that I will clone to the production box. It's the same hardware and I have done this before so it should work.

My question is about UIDs and GIDs. The 11.0 production box has UID 102 for sybase and 103 for sybaser and GID 102 for dba group. On the 11.11 box, UID 102 is smbnull and 103 is mysql and GID 102 is smbnull. These users do not exist on the production box.

Can I safely change the UIDs for smbnull and mysql and the GID for smbnull? That would be a whole lot easier than changing everything on the production box and risking disaster.

Who knew 10 years ago when the UIDs for sybase were first selected that the 100's would get used by something else?

Thanks,
Marlou

[A. Clay Stephenson · Accepted solution]

Nothing is really special about these UID's and GID's so, yes, it's safe to change them. You do need to do a find on the box searching for files with matching UID's or GID's and update them.

[SKSingh_1]

UIDs are used internally by kernel to manage all process resources.

user names are at higher level of unix structure and can be mapped to UIDs.

Any username can have any UID. However UID between 0-20 are special so except this range any unique ID should be used.

[Marlou Everson]

Thanks.

I also found that the man page for useradd and groupadd mentions that UIDs and GIDs from 0 to 99 are reserved. So I will change the UID and GID values. Only the mysql user owned any files and I changed them accordingly.

Marlou