CTDB

[Andrew Bartlett]

On Thu, 2007-08-16 at 21:43 -0600, Andrew B. Lundgren wrote:
> Andrew Bartlett wrote:
> > It is certainly more production ready than the alternatives for Samba on
> > clustered filesystems (which have too often boiled down to 'pray
> > hard' :-)
> >
> >   
> :)  Would that include the lustre pCIFS windows client? 

I was more referring to the installation of Samba on cluster FS nodes,
without a central locking mechanism, particularly for share modes (which
are not represented to the kernel). 

The problem is, it seems to work...

> >> Given a 4 node cluster, with file A residing on node 2.  When a windows 
> >> client requests file A, how does the data get to it?
> >>     
> >
> > The design CTDB is for doesn't have the file residing on node2 as much
> > as residing on a SAN, with access via any node.  If your 'SAN' actually
> > happens to be a cluster of servers with local disk, then perhaps you are
> > really looking for an MSDFS-based redirect setup (where your virtual
> > cluster simply redirects clients to the correct node to find their
> > file). 
> >
> >   
> >> Will the client go to any random node in the cluster and request the 
> >> file A and then be directed to node 2 to pull the file, or will the file 
> >> be pulled to the random node from node 2 and then sent to the client?  
> >>     
> >
> > To avoid that double-hop, then you probably want the MSDFS design.  
> >
> > If your kernel-level cluster FS hides the detail about where the file
> > actually is, then CTDB doesn't care about the details, as long as open()
> > gets the file. 
> >
> >   
> 
> My cluster will be made up of discs connected to the nodes, not on a 
> SAN, so perhaps that is the route I need to take.  I have spent a bit of 
> time reading about DFS and I know SAMBA is able to do that as well.  The 
> only question I am left with is managing disk space.  It seems that as a 
> portion of the DFS fills, I will have to augment that portion manually.  
> I still need to learn how to do that.

I'm sure someone has created complex management applications to handle
this kind of thing, but it very much depends on your needs.  

BTW, how are you handling data redundancy?  

Remember that any two systems that actively share the same directory
must be linked with CTDB.  If your system is not active/active for a
single directory, then you don't need CTDB.

Andrew Bartlett

-- 
Andrew Bartlett
http://samba.org/~abartlet/
Authentication Developer, Samba Team           http://samba.org
Samba Developer, Red Hat Inc.
-------------- next part --------------
A non-text attachment was scrubbed...
Name: not available
Type: application/pgp-signature
Size: 189 bytes
Desc: This is a digitally signed message part
Url : http://lists.samba.org/archive/samba-technical/attachments/20070817/624ca4fd/attachment.bin