Coda File System

Re: volume connection timeouts

From: Patrick Walsh <pwalsh_at_esoft.com>
Date: Mon, 02 May 2005 11:30:32 -0600
> Hmm, logs on Coda are tricky. Does apache close and reopen logs?
> I think it can create a lot of load on your Coda server, or easily
> go disconnected, in case of many updates.

	I'm not sure about this.  We haven't had troubles with the log volume
yet...

> It means you have a couple of bottlenecks at once.
> Even neglecting vmware overhead, you let client and server compete
> for resources like memory and disk access (and they are rather picky
> about syncing data to disk). It make disconnections probable.

	Really?  Our server farm design pretty much requires the backend
machines that act as coda servers to have coda clients running as
well.  

> > 	Local inconsistent object at ???/html/blah/blah, please check (this is
> > on the httpd volume)
> 
> It can mean e.g. that you went disconnected while copying the data
> to httpd directories and then at reconnection the client erroneously
> detected a conflict - that can rather easily happen.

	It would seem that this is what happened.  It looks like the volume was
write-disconnected because of a conflict, though still connected.  I
couldn't writereconnect it, but that was because there was a conflict.
Removing the conflict has fixed everything, but raises the question:
with only one client and one server and both strongly connected, how
does a conflict happen and how can it be avoided?  

> When do the errors show up? During or right after the copy? Later on?

	I'll get back to you on this question.

> I am not sure I understand your situation correctly, but I'd begin with
> setting up httpd so that its machine accesses Coda readonly.

	Except for the logs volume, it is restricted to readonly mode.

	If the vmware machine had more memory do you think we would stop seeing
these problems?  The production machines have 1gb of memory and plenty
of power.  Is there a way to make coda a little more tolerant so that it
doesn't slip into disconnected mode unless there's actually a
disconnection?  Our architecture is such that there should never be two
machines (or two coda users) who edit the same file.  Most coda clients
will be read only for most volumes.  Getting conflicts when there is
only one user, one client, and one server all strongly connected is a
bit baffling.


-- 
Patrick Walsh
eSoft Incorporated
303.444.1600 x3350
http://www.esoft.com/

Received on 2005-05-02 13:32:05