jtwang@cs.nctu.edu.tw writes:

When we upgrade the openldap server, the modifed "nis.schema" would be replaced with a unmodified "nis.schema".

Our servers will be down, because there are some strings in database which conflicts to "nis.schema".

Rename your hacked nis.schema and put it somewhere an upgrade will not touch.

May you change the default schema of the "gecos" field and make it to be able to carry dual-byte string?

Unfortunately, no. The schema is defined in RFC2307, which specifies IA5 String (ASCII) gecos. OpenLDAP follows that, and a change would cause interoperability problems with servers which still follow the RFC. You could write the RFC author and ask if there are plans to update to use Directory String.

So, not an OpenLDAP bug. This ITS will be closed.