The scenario

I have a SUSE SLES 11.1 SP1 machine as Samba master PDC with LDAP backend. In one share there are Database files for a Client-Server application. I log XP and Windows 7 machines to the local domain (example.local), the login is a little slow but works. In the client computers have an executable which opens, reads and writes the database files from the server share.

The Problem

When running Samba with LDAP password backend the client application runs VERY SLOW with a maximum transfer rate of 2500 MBit per second. If disable LDAP the client app speed increases 20x, with transfer rate of >50Mbit/sec and running smoothly.

I'm doing test with just two users and two machines, so concurrency, or LDAP size shouldn't be the problem here.

The suspect

LDAP, Smb.conf [global] section configuration.

The Question

What can I do? I've googled a lot, but still have no answer.

Slow smb.conf WITH LDAP

[global]
        workgroup = zmartsoft.local
        passdb backend = ldapsam:ldap://127.0.0.1
        printing = cups
        printcap name = cups
        printcap cache time = 750
        cups options = raw
        map to guest = Bad User
        logon path = \\%L\profiles\.msprofile
        logon home = \\%L\%U\.9xprofile
        logon drive = P:
        usershare allow guests = Yes
        add machine script = /usr/sbin/useradd  -c Machine -d /var/lib/nobody -s
 /bin/false %m$
        domain logons = Yes
        domain master = Yes
        local master = Yes
        netbios name = server
        os level = 65
        preferred master = Yes
        security = user
        wins support = Yes
        idmap backend = ldap:ldap://127.0.0.1
        ldap admin dn = cn=Administrator,dc=zmartsoft,dc=local
        ldap group suffix = ou=Groups
        ldap idmap suffix = ou=Idmap
        ldap machine suffix = ou=Machines
        ldap passwd sync = Yes
        ldap ssl = Off
        ldap suffix = dc=zmartsoft,dc=local
        ldap user suffix = ou=Users