Coda File System

Re: volume connection timeouts

From: Ivan Popov <pin_at_medic.chalmers.se>
Date: Mon, 2 May 2005 19:06:56 +0200
Hi Patrick,

On Mon, May 02, 2005 at 10:47:32AM -0600, Patrick Walsh wrote:
> 	We're having some problems in our testing now and I'm a little bit out
> of my depth.  We want to have coda as the shared storage for apache.
> The apache user, www-data, gets tokens that give it read-only access to
> the httpd directory and write access to the logs directory.  There's

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.

> nothing fancy in the setup.  For testing purposes, the coda client and
> server are on the same vmware machine.  There's only a single server.

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.

> 	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.

> 	We can reproduce this reliably on a clean install and a reboot doesn't
> fix it.  The files in httpd are put there using a standard `cp -dR`
> operation.  I'm not at all sure how to go about debugging the issue.  I

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

I am not sure I understand your situation correctly, but I'd begin with
setting up httpd so that its machine accesses Coda readonly.
You do not want your web server to update files on Coda, as it cannot
detect and resolve conflicts which it _may_ create. You can not count
with being strongly connected all the time.

Well, I do run scripts which update my mail directories day and night,
but they are quite Coda-aware - I doubt Apache is.

Then, may be Jan will make more sence of your logs and I can be totally off.

Best regards,
--
Ivan
Received on 2005-05-02 13:07:43