New Samba 3 messaging implementations

[James Peach]

On Tue, 2006-05-23 at 15:07 +0400, Aleksey Fedoseev wrote:
> Hi Team!
> 
> We are working on implementing Samba 3 for clusters. I've published the
> introduction, several clustering problems and proposed decisions (they
> were inspired by Volker's work) on the Samba wiki:
> http://wiki.samba.org/index.php/Clustered_Samba.
> 
> Any cluster implementation has to be based on some kind of messaging.
> The first step we planned is to implement socket-based (or any
> non-local) messaging in the trunk/samba-3 branch - upon that we'll be
> able to extend the messaging with tcp- or any other transport like MPI
> for cluster version of Samba.

See branches/tmp/jpeach-cluster for an implementation based on shared
TDB and TCP messaging. Note that the TCP messaging in this branch is
obsolete WRT top of tree since that was removed post-3.0.14.

This also includes auto-configuration and membership tracking which are
important issues for any clustered file server. You might also want to
look at the redirect VFS module.

> Our messaging research is published on the wiki:
> http://wiki.samba.org/index.php/Messaging. There three messaging
> implementations (tdb-based, unix-dgram-sockets from Samba4 and
> unix-stream-sockets) are listed, benchmarked and compared. Patches to
> the current Samba 3 branch can be downloaded there.

I presume the TDB messaging results were done mmap enabled? It would be
interesting to see a result for TDB with mmap disabled, since some
clusters (eps. heterogeneous ones) might not implement a coherent mmap.

Also, unix domain sockets don't work across the all clusters. Do you
know of any clusters that implement unix domain sockets?

> The main quesion is - what messaging extension can be added to trunk
> branch, so we'll continue clustering research and shall implement
> messaging-based locking for clusters?..

My view is that none of the current messaging implementations are
suitable for a cluster.

-- 
James Peach | jpeach at samba.org