To integrate into a common NAS storage while still using the NFS-option sec=sys UIDs shoult be synchronized across local systems. First step is to change the UID and GID to the desired ones:
sudo usermod -u [NEWUID] [USERNAME]
sudo groupmod -g [NEWGIO] [GROUPNAME]While usermod updates all files in the home-directory, all other files owner and group-settions must be updated as well:
find / -uid [OLDUID] -exec chown -v -h [NEWUID] '{}' \;
find / -gid [OLDGID] -exec chgrp -v [NEWGID] '{}' \;Of course, it would be much better to use actual Kerberos-credentials to limit accesses. But for a home installation with known users the above can limit the effort and ensure consistent file ownerships.