Coda File System

Re: replicated servers

From: Jan Harkes <jaharkes_at_cs.cmu.edu>
Date: Tue, 12 Apr 2005 16:46:38 -0400
On Fri, Apr 08, 2005 at 07:13:54AM -0400, Greg Troxel wrote:
> Good points, but it makes me comment that it would be nice to somehow
> have a server process or computer be able to operate in multiple
> realms.
> 
> realm foo.com   with servers at a.foo.com, b.foo.com, a.bar.com
> realm bar.com with servers at a.bar.com, b.bar.com, a.foo.com
> 
> sort of like backup dns arrangements.

Servers really have no idea what realm they belong to. If they did have
to know they would have to deal with multiple SCMs, several user/group
databases etc.

It is probably better to keep the servers as simple as possible. And
improve the volume location result to not just have a single IP address,
but return a hostname/port combination. That should make it possible to
have a.bar.com run both a server for bar.com on port 2432, and a
separate server for foo.com on port 2433 (or really any port).

Extend the /vice/db/servers file to "servername:port <serverid>"

Overall the changes should be fairly minimal, I think the VLDB file
already uses that server-id number. So it would be changing the bits
that parse the servers file, and adding a new GetVolInfo RPC that
returns the hostname and portnumber. I guess createvol_rep and other
scripts that use volutil will have to check the servers file as well to
see if one of the server we are trying to create the a replica on
happens to be running on an unusual port.

Jan
Received on 2005-04-12 16:48:25