Coda File System

Re: Intermediate Cache Servers

From: Jan Harkes <>
Date: Thu, 2 Dec 1999 12:28:16 -0500
On Wed, Dec 01, 1999 at 03:57:26PM -0600, wrote:
> I understand Transarc's AFS and DFS have the concept of an "intermediate
> cache server" where you can set up a read-only replica, where the system
> manages the contents and doesn't actually copy all the files, only the
> requested files (removing non-requested files from the server).
> Can this be done with Coda?

No this cannot be done. Thinking about it, it would be quite difficult
since that intermediate server would probably be something like a
modified client that exports its cache not through the kernel to
userspace, but through an RPC2 interface to other clients.

First of all, existing clients use a volume location database to find
the replicas for a volume. All replicas are considered to be equivalent,
both in cost of accessing, and read-only/read-write status. Second, what
happens if a conflict occurs between the intermediate and the real
servers. How is this fact forwarded to the real clients, and how could
they possibly fix the problem, as it is not a local conflict.

Received on 1999-12-02 12:30:17