[DRBD-user] SAMBA 3.0.9 writes surviving failover?

Musard, Kris Kris.Musard at spirentcom.com
Wed Nov 24 16:25:59 CET 2004

Note: "permalinks" may not be as permanent as we would like,
direct links of old sources may well be a few messages off.


AFS is Andrew File System.  It uses client side caching on file reads and
writes which is why I think it handles the failover so well.  You can learn
more about it at www.openafs.org  Thanks for the information on samba.  You
have saved me allot of time.

> -----Original Message-----
> From:	Philipp Reisner [SMTP:philipp.reisner at linbit.com]
> Sent:	Wednesday, November 24, 2004 4:54 AM
> To:	drbd-user at lists.linbit.com
> Subject:	Re: [DRBD-user] SAMBA 3.0.9  writes surviving failover?
> 
> On Tuesday 23 November 2004 22:21, Musard, Kris wrote:
> > I am working on a clustered fileserver using RedHat 9 + Heartbeat + DRBD
> > 0.7.5 + Samba 3.0.9.  I have been able to setup NFS and AFS fileservices
> so
> > that a file copy survives a failover and the file is not corrupted
> > (verified with cksum).  Is this possible with Samba?  So far when I
> > failover during the file copy through Samba I get the following error:
> >
> 
> In the case of NFS, this is possible because NFS has this stateless
> protocol
> (From my point of view a genial design decission of the initail NFS
> autors.)
> 
> What do you mean by AFS ? Apple File Sharing ? apfs ?
> 
> > "Cannot copy <filename>:an unexpected network error occurred"
> >
> > I only miss 1-2 pings during the failover.  I have my drbd mirrored
> > directory as /smb and have linked /var/lib/samba and /etc/samba to
> > /smb/varlibsamba and /smb/samba.  In my smb.conf file I have the locks
> and
> > logs directories set to /smb/locks and /smb/logs respectively.  I have
> my
> > service address on a dedicated ethernet interface and am failing over
> the
> > MAC address along with the IP.  I have set the smb.conf file to restrict
> to
> > this interface.  Any assistance would be appreciated.
> 
> The SMB protocol is not state-less, it relies on retries. But the nice
> thing
> is that the client tells you that there was an error. So you have to
> retry.
> 
> Awkward would be it the SMB client would not tell you that it failed...
> 
> BTW, so achiev seamless SMB failover we would need to be able to migrate
> open sockets. Werner Almesberger is working on this toppic. [He gave a 
> speech about it on the last Linux Kongress.]
> 
> Conclusio: Today it is not possible to do SMB failover without retry.
> 
> Note: If the failover happens while no file is in flight, the client
>       will not notice the failover, because there are some retry
>       mechanism in Window's SMB client implementation.
> 
> -Philipp
> -- 
> : Dipl-Ing Philipp Reisner                      Tel +43-1-8178292-50 :
> : LINBIT Information Technologies GmbH          Fax +43-1-8178292-82 :
> : Schönbrunnerstr 244, 1120 Vienna, Austria    http://www.linbit.com :
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