[Samba] LVS and SAMBA

Ciro Iriarte cyruspy at gmail.com
Sun Nov 21 14:02:44 MST 2010

2010/11/19 Jim McDonough <jmcd at samba.org>:
> On Thu, Nov 18, 2010 at 3:56 PM, Michael Adam <obnox at samba.org> wrote:
>> Ciro Iriarte wrote:
>>> 2010/11/3 Volker Lendecke <Volker.Lendecke at sernet.de>:
>>> > On Wed, Nov 03, 2010 at 11:03:20AM -0300, Ciro Iriarte wrote:
>>> >> Hi, would it be possible to  run two nodes with SAMBA+LDAP and a OCFS2
>>> >> filesystem, with LVS load balancing WITHOUT CTDB?. This would be
>>> >> relying only on OCFS2 file locking. The idea is to provide
>>> >> authentication, HA file service and load balancing.
>>> >
>>> > That would cause data corruption. As far as I know (please
>>> > correct me if I'm wrong) OCFS2 does not support the full
>>> > semantics required for share modes, oplocks and all the
>>> > other fancy cifs features that Samba provides. That's the
>>> > point of the ctdb and clustered samba combo.
>>> >
>>> > Volker
>>> >
>>> Well, the new "cool" feature on OCFS2 is fcntl, apparently is not
>>> enough. With CTDB I see that nodes use the same netbios name. How
>>> would that affect domain controller feature?. I won't like to build
>>> other server pair just for PDC/BDC....
>> When you think a little about it you will agree that
>> when serving the same folder from a cluster file system
>> like ocfs2, as mounted on two different nodes, as
>> samba shares from these nodes, then you will have to
>> configure the two sambas to use the same netbios name.
>> Not only that, but you will also have to make sure that
>> the windows SID --> unix ID mappings are identical.
>> (Unless, of course, you like data corruption. ;-)
>> And so on.
>> The typical use case for a clustered samba with ctdb
>> is a file server that is member in a domain, but you
>> can in principle also run samba as a clustered Domain
>> controller on the cluster. THis will just be one DC
>> then (since the samba's on the nodes will have to
>> appear as one server together), but this way you could
>> replace the PDC/BDC replication, failover and load
>> balancing mechanism of the classical PDC/BDC scheme
>> buy using e.g. one clustered PDC. This could even use
>> tdbsam then (instead of ldapsm), since replication
>> is done by CTDB then.
>> I personally have not done such a setup. But it should
>> not be a big problem. Be sure to use the "cluster addresses"
>> variable in smb.conf here to make nmbd happy.
>> Maybe Jim McDonough can share some of his experiences here? :-)
> I think you've basically covered it, Michael.
> This setup is supported on SLES11+HAE as described here.  Ok, we're
> reworking the ctdb resource agent, but if you run ocfs2 under the HA
> stack, and ctdb outside this, it works just fine.  A new resource
> agent is coming soon, or if you've got support on SLES11SP1+HAE,
> please contact Novell support.
> --
> Jim McDonough
> Samba Team
> SUSE labs
> jmcd at samba dot org
> jmcd at themcdonoughs dot org

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