According to the following links, varchar(N) is indeed in bytes:

• http://stackoverflow.com/questions/16956555/ibm-db2-9-7-varcharn-does-n-stand-for-characters-or-bytes-in-utf-8
• http://www-01.ibm.com/support/knowledgecenter/SSEPEK_10.0.0/com.ibm.db2z10.doc.intro/src/tpc/db2z_stringdatatypes.dita?lang=en

When trying to insert a value into the database that is N characters, but more than N bytes, it gives the following error:

IBM DB2 ERROR: [-433] 22001 [[IBM][CLI Driver][DB2/LINUXX8664] SQL0433N  Value "????????? ???????? ? UTF-8..." is too long.  SQLSTATE=22001]

Ideally, if we find a way, we should make it possible to store N characters. If not, we should at least cut the value we are trying to insert to N bytes so that there are no SQL errors.