On 11/15/2021 6:48 AM, Simon Matter wrote:
I've created a script which uses `chown' to recursively change UIDs and GIDs. I don't remember exactly but I think I made it run for every user in parallel and it finished quite fast considering the fact that it had to traverse the whole storage consisting of millions of files. I could then later just rsync everything to the new box without ant UID/GID conversion.
rsync by default copies by name, not UID/GID. So you can let the new system assign numbers based on the new limits and let rsync do the conversion.
You could also just keep the old numbers. AFAIK, no numbers in the 500-999 range have been globally registered. Create your users with their old IDs on a minimal system before installing any optional packages that might try to allocate a system UID from the same range. Then the optional packages will allocate from any "holes" in that range.
Other UID ranges you want to dodge are listed here: