Coda File System

Re: Final explanation about server replication?

From: Jan Harkes <jaharkes_at_cs.cmu.edu>
Date: Fri, 16 Nov 2001 15:08:07 -0500
On Fri, Nov 16, 2001 at 07:10:42PM +0000, Valerio Morettini wrote:
> 6) edited /vice/db/servers to look like:
> homer           1
> flanders        2
> 
> 7) edited /vice/db/VSGDB to look like:
> E0000100 homer
> E0000102 flanders
> E0000104 homer flanders

You should restart all servers after editing these files.

> 9) 
> [root_at_homer /]# createvol_rep www E0000104 /usr/www
> Volume www already exists in /vice/db/VRList

You already created a singly replicated volume named 'www' on homer
earlier so ofcourse this won't work.

> changed the name, just to test:
> [root_at_homer /]# createvol_rep realwww E0000104 /usr/www
> 
> 10) now the manual states "mount the volume", and i really can't
> understand what i have to do next! ( isn't mounting an operation that
> should be performed by clients only??)
> I tried cfs mkmount /usr/www

How about running a coda client, and doing cfs mkm /coda/realwww realwww
Or change the name of the rootvolume to realwww by editing
/vice/db/ROOTVOLUME on the SCM and then reinitializing the client so
that it mounts the new volume as it's replicated root.

btw. you probably want to have at least a separate rootvolume because it
is a pain repairing any conflicts that occur in the root of your /coda
tree as we can't turn the /coda object into a symlink without losing
access to a control file that we need to do the necessary repair
operations.

> Obviously, at this point replication of the /usr/www dir among 
> the 2 server does not work yet...

I also believe you've got the whole idea of how the replication works
wrong.

The way you've configured it, /usr/www (normally /vicepa) will store a
directory tree of anonymous file data objects. The server's RVM will
hold associated metadata and this data and metadata is combined by the
client and exported through the /coda mountpoint.

Jan
Received on 2001-11-16 15:08:22