Propagating file locks across network

Dominick Layfield dom.layfield at
Thu Jul 12 01:15:26 GMT 2007

tridge at wrote:
 > As Ronnie says, ctdb is the way to go for this.
 > I'd also suggest you look at
 > for a tool to test to see if your distributed filesystem has the
 > necessary semantics to support clustered Samba.

I've just started looking at the CTDB documentation, and wasn't not sure whether 
our filesystem had sufficient functionality.   That's pretty cool that you wrote 
a tool specifically for that!

My guess, however, is that CTDB is attempting to solve a very different problem 
(Samba distributed over a small number of locally-connected servers) and is not 
directly suitable for our purposes.

Most distributed filesystems provide coherence guarantees that we specifically 
do not.  Our filesystem is designed to operate with highly unreliable 
connectivity between nodes.  In such circumstances, a traditional distributed 
f/s architecture provides unreasonably limited availability.  We use an 
"optimistic replication" architecture which allows conflicting file versions to 
develop in isolated subnets.

What happens to CTDB if the cluster is split into two (or more) subnets?  Will 
each fragment continue to operate normally?   That's the goal I'm after.

Anwyay, I'll download the CTDB code, and ping-pong, and have a play!


-- Dominick

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