Coda File System

Re: Can I control which volumes are replicated on which servers?

From: Jan Harkes <>
Date: Thu, 25 Jan 2001 12:04:21 -0500
On Thu, Jan 25, 2001 at 10:33:47AM -0500, Brad Clements wrote:
> I'm setting up a test wide area Coda replication
> (2 servers in US, 1 in Netherlands, 1 in New Zealand)
> I'd like to limit which volumes get replicated onto the non-US servers. Is 
> there any way to do that? 

E00000100 us-server1 us-server2
E00000101 nl-server1
E00000102 nz-server1
E00000200 us-server1 us-server2 nl-server1 nz-server1

 Then you can create volumes replicated across the different VSGs like
    createvol_rep us-rep2-vol E00000100 /vicepa
    createvol_rep nl-rep-vol E00000101 /vicepa
    createvol_rep nz-rep-vol E00000102 /vicepa
    createvol_rep everywhere-vol E00000200 /vicepa

The Coda design assumes co-located servers, with a fast/reliable
connection between them. So I'm not yet sure how well server-server
resolution would work in a WAN setp. Keep mostly read-only volumes
across all servers.

5.3.11 clients are (finally) smart enough to do fetches from the
`strongest' server, so they should hit the local server as long as it is
available. In strongly connected mode, writes will go to all servers, so
clients will suffer from having to push the data to the distant replica.

In weakly connected (trickle-reintegration) mode, updates should be sent
to the nearest server and server-server resolution is triggered. This
creates greater window of opportunity for conflicts. The servers also
lock any volumes that are resolving, so clients will be blocked out
until the servers are back in sync.

Received on 2001-01-25 12:04:38