samba - May 2007 - Question about multiple ldap backend (as failover/load balance)

Hello

OK, in my case, there is only one samba server acting as PDC.
On the PDC, it has a openldap server as backend.

I have configured another server as the slave ldap server. slave ldap
server will pool data by syncrepl.

There are some spaces in samba/smbldap-tool that we can configure
multiple ldap servers (or load balance by use of DNS)

What happen if the PDC write data to the slave ldap server? (or the
master ldap server failed, data has to write to the slave ldap server.
and then the master ldap server comes online)

The main problem is that the master and slave ldap server will be out
of sync. Can samba auto detect and fix it?

Thanks
Patrick


 
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> The main problem is that the master and slave ldap server will be out
> of sync. Can samba auto detect and fix it?
No.

-- 
Adam Tauno Williams, Network & Systems Administrator
Consultant - http://www.whitemiceconsulting.com
Developer - http://www.opengroupware.org

Hi

Am Mittwoch, 30. Mai 2007 11:06 schrieb Patrick Dung:
> Hello
>
> OK, in my case, there is only one samba server acting as PDC.
> On the PDC, it has a openldap server as backend.
>
> I have configured another server as the slave ldap server. slave ldap
> server will pool data by syncrepl.
>
> There are some spaces in samba/smbldap-tool that we can configure
> multiple ldap servers (or load balance by use of DNS)
>
> What happen if the PDC write data to the slave ldap server? (or the
> master ldap server failed, data has to write to the slave ldap server.
> and then the master ldap server comes online)
you should not be allowed to make changes on a LDAP slave, which has to be 
made sure by appropiate LDAP-ACLs. For write operations clients connected to 
the slave must be forwarded to the master-ldap by ldap referrals.
> The main problem is that the master and slave ldap server will be out
> of sync. Can samba auto detect and fix it?
This would be a feature of the LDAP-Server, as samba can't cover all 
attributes other clients may have changed. If you need this look out for an 
LDAP sevrer which supports multi-master modes.

By the way: samba runs fine with an read-only copy of your LDAP as long as you 
don't need to administrate something or a password needs to be changed. This
can cover downtimes of you LDAP-master without user service interruptions.

Regards
Ingo Steuwer
> Thanks
> Patrick
>
>
>
> ___________________________________________________________________________
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-- 
Ingo Steuwer           Projektmanagement        steuwer@univention.de
Univention GmbH        Linux for your Business  fon: +49 421 22 232-43
Mary-Somerville-Str.1  28359 Bremen             fax: +49 421 22 232-99
                       http://www.univention.de

Hello

1.
OK, after searching, I found that openldap is a single master model.
http://www.openldap.org/faq/data/cache/1240.html
I think it will not change in foreseeable future.

In my previous mail, I said the ldap servers may be out of sync.
But actually, under Openldap 2.3, it will not be the case.
Slave ldap server is required to add the 'updateref' directive which
refer all modifiy/update to the current replica.
If 'updateref' directive is missing, the slave server refuse to make
changes to the directory.

BTW, openldap 2.4 may have a new thing called mirror mode:
http://www.mail-archive.com/openldap-software@openldap.org/msg08188.html

2.
I found that Fedora DS can implement multi master mode.
http://directory.fedoraproject.org/wiki/FAQ#How_does_the_Fedora_Directory_Server_multi-master_replication_work.3F

With FDS, would samba be able to provide HA/multimaster AD?

Thanks
Patrick

--- Patrick Dung <patrick_dkt@yahoo.com.hk> wrote:
> Hello
> 
> OK, in my case, there is only one samba server acting as PDC.
> On the PDC, it has a openldap server as backend.
> 
> I have configured another server as the slave ldap server. slave ldap
> server will pool data by syncrepl.
> 
> There are some spaces in samba/smbldap-tool that we can configure
> multiple ldap servers (or load balance by use of DNS)
> 
> What happen if the PDC write data to the slave ldap server? (or the
> master ldap server failed, data has to write to the slave ldap
> server.
> and then the master ldap server comes online)
> 
> The main problem is that the master and slave ldap server will be out
> of sync. Can samba auto detect and fix it?
> 
> Thanks
> Patrick
> 
> 
>  
>
____________________________________________________________________________________
> Expecting? Get great news right away with email Auto-Check. 
> Try the Yahoo! Mail Beta.
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> 


       
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