You can not convert a hdb backend into a mdb backend without changing the underlying database. slapcat(8) the hdb database into a file and slapadd(8) the file into a mdb backend.

Hello, but it works. I have made the following changes to the config.ldif file. Then I replayed the LDIF file into an empty ldap directory with slapadd: ... olcModuleLoad: {0}back_mdb

dn: olcBackend={0}mdb,cn=config olcBackend: {0}mdb

dn: olcDatabase={1}mdb,cn=config objectClass: olcMdbConfig olcDatabase: {1}mdb olcDbMaxSize: 1073741824 structuralObjectClass: olcMdbConfig ...

Thank you in advance for your support