Coda File System

Re: replication

From: Patrick Walsh <>
Date: Tue, 31 May 2005 08:28:18 -0600
On Sat, 2005-05-28 at 11:46 -0400, Jan Harkes wrote:
> When client 1 writes, he writes to all available replicas. The server
> doesn't do anything special here, so the data only exists on server A.
> Now server A does send a callback to all clients that have fetched a
> copy of the file or directory that was involved in the update. If your
> 'filter' is good enough, this would mean that client 2 doesn't even see
> the callback, but some client 3 might have received it.


> > 	If that's the case, then Client 2 should be able to see the new file
> > fairly quickly, right?  Alas, in my tests, it takes between 5 and 10
> > minutes before Client 2 can see the change, regardless of how many times
> > I try to flush the cache, checkservers or checkvolumes.
> The fact that client 2 sees the update at all means that there must be
> some client 3 that happens to see both servers, which gets the callback.
> Then during the next cache validation/hoard walk, which occurs about
> once every 10 minutes, that client fetches the attributes from both
> servers, notices the version skew and triggers the resolution process.

	OK, this makes sense.  Thanks for clarifying how this works.

Patrick Walsh
eSoft Incorporated
303.444.1600 x3350

Received on 2005-05-31 10:32:46