Coda File System

Re: Building a coda "appliance"

From: <>
Date: Sat, 30 Jun 2007 18:01:41 +0200
Hi Yan,

On Sat, Jun 30, 2007 at 08:08:17AM -0700, Yan Seiner wrote:
> Do I read your comments correctly in that Coda doesn't do file locking 
> across the network?

Unfortunately, there is no file locking in Coda.

There happens to be an unused flag in ACLs, 'k', inherited from AFS,
but it does not mean anything.

> Or would that just be the consequence of my proposed samba<->coda 
> setup?  Would I get file locking if each PC was a Coda client?


> In our situation, we work with "assemblies" where each assembly consists
> of many separate files, which are opened concurrently either RO or RW,
> and file locking across the network is essential to prevent corruption
> of the entire assembly.

I guess each assembly is used locally, not concurrently across the globe.
Then you have to use a more "local" file system, which could give you
the locking, and do the global synchronization offline.

Resilience to network failures (one of the major Coda advantages)
is hardly compatible with remote locking.

I would suggest doing unison-like synchronization via an extra node,
thus eliminating the need to take both sides down for synchronization

A <=> C
then at some other point in time C <=> B
and so on

It does not matter where C is located,
but it has to have the necessary amount of disk.

Eventually all modifications will propagate in both directions.

(Coda could act as the C-node, but that looks hardly useful in your scenario
where most of the data needs locking => explicit synchronization)

Best regards,
Received on 2007-06-30 12:03:15