[Samba] samba 4 DC slow users bulk load

Andrew Bartlett abartlet at samba.org
Sun Oct 6 14:49:40 MDT 2013

On Sun, 2013-10-06 at 13:48 +0300, Nikos Mitas wrote:
> Hello,
> i have successfully installed samba 4 on three vmware VM's and everything
> works fine (join pc to domain, user login, dns updates, ntp),
> but i am facing some performance problems during users bulk loading.
> my environment:
> 1st DC: RedHat Linux v6.4,samba 4.1rc4,dns 9.9.3P2,ntp
> 2nd DC:RedHat Linux v6.4,samba 4.1rc4,dns 9.9.3P2,ntp
> 3rd DC:RedHat Linux v6.4,samba 4.1rc4,ntp
> to bulk load the users (around 20.000 accounts) i am using IBM Tivoli
> Identity Manager to automatically create the AD accounts into Samba
> but the performance is poor. 120 users per hour at most.
> Any ideas what to check or what needs to be tuned?

We need to work out what specifically is slow, so we can deal with it. 

If you can capture the ldap server task under 'perf record -g -p PID'
that might give some clues.  It shouldn't take 30 seconds to add a user,
but at this size many O(n^2) things blow up badly, and we may need to
re-investigate better approaches in some cases. 

Also, ensure you have plenty of memory, and for the period of the
import, run samba under TDB_NO_FSYNC=1.  This makes samba unsafe against
a poweroff event (equivalent to linking with libeatmydata), so don't use
this in production, but it will make things much, much faster for the
initial import. 

Andrew Bartlett

Andrew Bartlett

Andrew Bartlett
Authentication Developer, Samba Team           http://samba.org
Samba Developer, Catalyst IT                   http://catalyst.net.nz

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