hdb and mdb have different search results/behaviour

[<Juergen.Sprenger@swisscom.com>]

Hi,

I have running OpenDLAP 2.4.35 on  Gentoo Linux and wanted to make some tests with mdb.

Slapd was running fine with hdb, no problems so far. 
Then I exported contents via slapcat and switched config to mdb. 
When slapd started using mdb no users from directory were shown by 'getent passwd':

### hdb part ####
# using hdb parameters
database        hdb
dirtyread
cachesize       150000
cachefree          100
idlcachesize    450000
dncachesize     100000

# slapadd from backup and run slapd with hdb backend
/etc/init.d/unscd stop
/etc/init.d/slapd stop
rm /var/lib/openldap-data/*
rm -rf /etc/openldap/slapd.d/*
cp -p /etc/openldap/DB_CONFIG /var/lib/openldap-data/
cp -p /etc/openldap/slapd.conf.hdb /etc/openldap/slapd.conf
su ldap -c '/usr/sbin/slapadd -f /etc/openldap/slapd.conf -l odsldap-dev.ldif'
/etc/init.d/slapd start
/etc/init.d/unscd start
slapcat -f /etc/openldap/slapd.conf -b dc=scom | md5sum
# 73850f9a3f7ff9d3d1ddb7663cd046a6  -

getent passwd
# all users shown, everything ok

### mdb part ####
# using mdb paramters
database        mdb
dbnosync
maxsize 2094967296
searchstack 64

# slapadd from backup and run slapd with mdb backend
/etc/init.d/unscd stop
/etc/init.d/slapd stop
rm /var/lib/openldap-data/*
rm -rf /etc/openldap/slapd.d/*
cp -p /etc/openldap/slapd.conf.mdb /etc/openldap/slapd.conf
su ldap -c '/usr/sbin/slapadd -f /etc/openldap/slapd.conf -l odsldap-dev.ldif'
/etc/init.d/slapd start
/etc/init.d/unscd start
slapcat -f /etc/openldap/slapd.conf -b dc=scom | md5sum
# 73850f9a3f7ff9d3d1ddb7663cd046a6  -

getent passwd
# no users from ldap shown

Am I missing something  when setting up and using mdb? 
Both backends have exactly the same content, and so the results for searches should also be identical.

Regards

Jürgen Sprenger