Coda File System

Re: New installation issues

From: Jan Harkes <>
Date: Fri, 9 Feb 2007 16:54:04 -0500
On Fri, Feb 09, 2007 at 12:36:11AM -0500, Davor Ocelic wrote:
> 	On the client side (also from CVS head), I edited venus.conf
> to point to the proper device file (/dev/.static/dev/cfs0) and
> edited the 'realms' file to include a line like:
> re.alm
> 	Venus started successfully and typing
> cfs lv /coda/ produced meaningful output.

If you address your server directly like that, you don't need a realms
file at all.

Technically when a Coda client wants to talk to a group of Coda
servers it needs to connect to one or more servers in the group and asks
those servers where volumes are located.

So if you connect to /coda/, your client simply asks
'' what the root volume is, how many replicas there are and
where those replicas are located. So given that one server a client can
discover that some volume replicas may be located on other servers in
your domain. In fact, we used to have a single root server with no
volumes. It's only function was to handle volume location queries and
redirect clients to the servers that did store data.

The only issue with this is that if that one server goes done, clients
cannot discover the location of any Coda volumes for which it doesn't
have cached information in the realm, even when the rest of the servers
are available.

So for high availability purposes we added DNS SRV record lookup, now a
client checks the DNS record for, and ideally gets a
list of several servers that can be used for volume location queries
(technically every Coda server has a copy of all the critical data in
/vice/db and so every server is capable of responding to volume location

So great we've got DNS SRV record lookup and we can publish a couple of
servers as representatives for our realm. However our DNS servers do not
support SRV records, don't really know why. So we added an alternative
lookup mechanism, and similar to how /etc/hosts works we first check

So with the realms file you specified it simply says that whenever that
specific clients tries to access '/coda/re.alm/', it should get volume
location information from

> 	I ran  clog user_at_re.alm  , but I got a message along the 
> lines of "Cannot resolve any auth2 servers in realm re.alm".
> Repeated invocations of the command prompted for a password

This wouldn't have gotten the token you wanted anyways, the resulting
token would have give you permission to access files in /coda/re.alm/
and not /coda/

If you access '/coda/', you should obtain tokens as

Although both really map to the same server and root volume, the client
doesn't realize this. And the really messy part is that the server is
unable to distinguish requests for /coda/re.alm from /coda/
and will only set up a single callback connection as a result the client
ends up with a connectivity issues (server reachability is defined as
having an established callback connection) and possibly stale data in
either of the two trees.

Now since you built from source, did you override the configure prefix
or did everything get installed in /usr/local/{bin,sbin}. It is quite
likely that clog is trying to use /usr/local/etc/coda/realms and as such
it doesn't see your definition and will fall back on trying to resolve
for DNS SRV records which don't exist.

> without giving the error message again, but the authentication
> didn't succeed ('ctokens' reported "...venus ioctl: Not authenticated..."
> in its output).
> 	I tried providing -host option to clog, both as a FQDN server
> name and an IP address, but the outcome was the same.

Another thing to check is whether the auth2 daemon is actually running

Received on 2007-02-09 16:56:05