Coda File System

Re: Coda newbie

From: Robert Watson <>
Date: Tue, 02 Sep 2008 06:33:18 -0400
On Fri, 25 Jul 2008, Andy Valencia wrote:

> --------
> [ writes:]
>> If the distribution does not cripple the kernel, Coda will work fine.
> FYI, for FreeBSD 7.0 I found that the latest Coda stuff was in the ports 
> tree, but this didn't include the kernel module.  All I could find on the 
> kernel side was back an entire revision.  I was in an environment which 
> already had Coda running, so I didn't want to drop back a rev.
> I queried here, and didn't get a response.  So I'm assuming that tracking 
> FreeBSD is not much of a priority.

(Joining this thread late due to a busy August)

As far as I'm aware, the kernel module shipped in FreeBSD 7.0 should speak 
fine to the latest Coda user components.  I don't believe there have been 
significant changes in the protocol between Coda kernel and user parts in 
quite a long time.

I have made significant improvements to the kernel module that will be shipped 
with FreeBSD 7.1 in a couple of months.  It should be possible to compile the 
new version of the kernel module on a 7.0 system as they have basically the 
same KPI for VFS.  It may even be possible to simply use the 7.1 Coda kernel 
module on 7.0, although I would discourage that.

I've been thinking about removing support for older Coda versions in the 
FreeBSD module, since they're done at compile-time, and this list is probably 
a good a list as any to ask about it.

Finally, as Rune reports, there is a reported issue with the Linux ABI 
emulation and the Coda kernel modules.  It's unclear to me whether this is a 
bug in the ABI emulation layer or the Coda kernel module, and unfortunately 
I've not had time to track down that issue.  It would be good to get that 
fixed before FreeBSD 7.1 ships.

Robert N M Watson
Computer Laboratory
University of Cambridge

> Thus, FreeBSD didn't work out for me, so I stayed with Linux.
>> Some distros' packages can be old or broken. (e.g. Gentoo ebuild has been
>> broken for a long time, placing Coda mount at some other place than /coda.
>> 2008-07-12 I got a reply to my bug report from 2006-08-17 - note the years.
>> Now there is an experimental ebuild which adds a symlink /coda -> ....
>> so it _may_ work on Gentoo now)
> Note also I had to punt entirely on Coda after some files dropped out to
> un-readability even with my greatest care to cleanly shut down clients
> and servers.  I was able to dredge the basic contents out of the raw
> storage files, but I decided that even with its potential capabilities,
> it was going to be a net loss of my time to try and use Coda.  This was
> the latest Coda from CMU's site, compiled for Kubuntu Gutsy (which was
> the latest at that time, as I recollect).
> So proceed with caution.  As far as I can tell, Coda doesn't scale to
> modern media sizes.  And you will want a non-Coda backup system which is
> run often enough to stay very current.  And I wouldn't recommend
> deploying it except where it's OK to have unscheduled 1-2 hour outages
> while somebody goes and tinkers with Coda when something bad/unexpected
> happens.
> $0.02,
> Andy Valencia
Received on 2008-09-02 08:31:42