[Samba] Samba 4 LDAP/LDB search speed

[Roel van Meer]

Hi list,

we're in the process of converting our Samba 3 / OpenLDAP systems to Samba4.  
Since these machines also run applications (Postfix, Zarafa) that  
retrieve their information from LDAP, performance of the LDAP server is  
quite important to us.

While testing, it seems that the S4 LDAP server is a lot slower than  
OpenLDAP. So, I would like to ask two questions:

1. What is the expected performance of the S4 LDAP server? E.g. if someone  
could give me a rough estimate on the number of simple queries per second on  
average hardware, then I can see if my setup is performing as expected or  
not.

2. Are there settings in the config that can improve the performance of the  
LDAP server?

Currently, I'm testing with a simple shell script that runs an ldapsearch  
command that retrieves a single user entry, 1000 times (see below). With  
OpenLDAP, this takes about 2.5 seconds, with Samba 4 it takes around 30  
seconds. This is with samba 4.1.11, ldb 1.1.17. The database has around 300  
entries, not following the returned references.

I've tried using Matthieu Patou's patches from
http://git.samba.org/?p=mat/samba.git;a=shortlog;h=refs/heads/ldb_perfs
on my ldb, but that did not notably change the speed (which might very well  
be that I am not testing correctly).

Thanks for any info on this!

Regards,

Roel


#!/bin/sh
for i in `seq 1 1000`; do
    ldapsearch -x -h localhost -p 389 -D cn=dago,cn=Users,dc=s4,dc=local \
-w password '(&(objectclass=user)(cn=dago))' &>/dev/null
    errno=$?
    if [ "$errno" != 0 ]; then
        echo "break at $i"
        break
    fi
    echo $i
done