[Linux-cluster] Samba Statefull Failover

Wed Jun 23 20:43:00 UTC 2010

Hi Chris.

Sweet I will give that a go (upgrading to dev version of SMB and using
a later SMB client - Win7 or the like)

Thanks a mill

Jay

On 23 June 2010 21:11, Christopher R. Hertel <crh at ubiqx.mn.org> wrote:
> Jason,
>
> You're correct.  Sorry.  I'm a protocol geek, and I was addressing the
> protocol issues.
>
> Samba 3 has SMB2 in the development tree, but not yet released as stable.
> It should be pretty close to a testing release, however, so folks interested
> in testing SMB2 support should watch the samba-technical list.
>
> If you are running any pre-Vista Windows products, then you are also correct
> that SMB2 won't be supported on those.
>
> Having said all of that...  The problem is that the Windows SMB1 clients
> have no mechanism for recovering if the TCP connection is lost.  If they are
> using OpLocks, for instance, all cached updates are lost if the connection
> goes down.  The clients simply throw away state and start over.  If the
> applications running on those clients do not know how to re-establish the
> correct state then they will lose data.
>
> This has nothing to do with CTDB, since it all happens on the client side.
>
> SMB2, however, has what are called "persistent file handles".  The Windows
> SMB2 client can maintain state even if the TCP connection fails.  When the
> connection is re-established, the client can resynchronize with the server
> and all is well.
>
> Chris -)-----
>
> Jason Fitzpatrick wrote:
>> Hi Chris..
>>
>>>From reading  up on the SMB2 protocol it seems that this is
>> implemented within Vista and greater MS clients, but I do not seem to
>> be able to track support for SMB2 within SAMBA
>>
>> I see that there is a Samba4AD project but cannot find rpms for RHEL
>> and am a bit cagey about putting a dev version onto a critical file
>> server.
>>
>> And the Citrix (client) servers are 2003 SMBv1 anyway so that kind of
>> kills that anyway.
>>
>> Thanks
>>
>> Jay
>>
>> On 22 June 2010 17:08, Christopher R. Hertel <crh at ubiqx.mn.org> wrote:
>>> Please note that the SMB/CIFS protocol itself does not gracefully recover
>>> from a failover.  SMB2 is much better in this regard.  This is a client-side
>>> problem due to limitations in the protocol and client expectations.
>>>
>>> Chris -)-----
>>>
>>> Frank de Groodt wrote:
>>>> Make sure you use virtual public ip addresses managed by CTDB, not the ones bound to your NICS.
>>>>
>>>> Frank.
>>>> ________________________________________
>>>> From: linux-cluster-bounces at redhat.com [linux-cluster-bounces at redhat.com] On Behalf Of Abhijith Das [adas at redhat.com]
>>>> Sent: Tuesday, June 22, 2010 4:33 PM
>>>> To: linux clustering
>>>> Cc: Sumit Bose; Gunther Deschner; Simo Sorce
>>>> Subject: Re: [Linux-cluster] Samba Statefull Failover
>>>>
>>>> ----- "Jason Fitzpatrick" <jayfitzpatrick at gmail.com> wrote:
>>>>
>>>>> From: "Jason Fitzpatrick" <jayfitzpatrick at gmail.com>
>>>>> To: linux-cluster at redhat.com
>>>>> Sent: Tuesday, June 22, 2010 6:43:36 AM GMT -06:00 US/Canada Central
>>>>> Subject: [Linux-cluster] Samba Statefull Failover
>>>>>
>>>>> Hi all
>>>>>
>>>>> Just wondering if it is possible to statefully migrate smb
>>>>> connections
>>>>> between cluster nodes, I am running ctdb (Samba's Cluster software)
>>>>> but all connections are dropped when the service is failed between
>>>>> nodes
>>>>>
>>>>> Setup is as follows
>>>>>
>>>>> 2 node cluster
>>>>> DRBD backend shared storage in Master Master configuration
>>>>> cman presenting GFS2 /Storage folder
>>>>> Samba + Winbind + CTDB used to present /Storage/Test_Share via
>>>>> \\clustername\test_share (both nodes are AD integrated)
>>>>>
>>>>> Connections to replicated storage are working fine, AD accounts are
>>>>> authenticated correcly and smbstatus shows that CTDB is load
>>>>> ballancing the cluster address between nodes correctly,
>>>>>
>>>>> When I run ctdb shutdown I expect existing connections to be migrated
>>>> Also, I think "ctdb shutdown" is not the right command (Use "ctdb disable", it
>>>> should all be in the man pages). Only one node should fail so that the
>>>> other node can take over the IP address. If the IP address is not taken
>>>> over, the clients will probably not be able to reconnect.
>>>>
>>>> Cheers!
>>>> --Abhi
>>>>
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>>>> https://www.redhat.com/mailman/listinfo/linux-cluster
>>>>
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>>> --
>>> "Implementing CIFS - the Common Internet FileSystem" ISBN: 013047116X
>>> Samba Team -- http://www.samba.org/     -)-----   Christopher R. Hertel
>>> jCIFS Team -- http://jcifs.samba.org/   -)-----   ubiqx development, uninq.
>>> ubiqx Team -- http://www.ubiqx.org/     -)-----   crh at ubiqx.mn.org
>>> OnLineBook -- http://ubiqx.org/cifs/    -)-----   crh at ubiqx.org
>>>
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>>> Linux-cluster at redhat.com
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>>>
>>
>>
>>
>
> --
> "Implementing CIFS - the Common Internet FileSystem" ISBN: 013047116X
> Samba Team -- http://www.samba.org/     -)-----   Christopher R. Hertel
> jCIFS Team -- http://jcifs.samba.org/   -)-----   ubiqx development, uninq.
> ubiqx Team -- http://www.ubiqx.org/     -)-----   crh at ubiqx.mn.org
> OnLineBook -- http://ubiqx.org/cifs/    -)-----   crh at ubiqx.org
>
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> Linux-cluster at redhat.com
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>

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