Coda File System

Re: Problem with mv(1)

From: Michael Salzmann <>
Date: Sun, 29 Nov 1998 18:17:53 +0100
On Fri, Nov 27, 1998 at 04:16:56PM -0500, Peter J. Braam wrote:
> Michael,
> Yes what you show is slow, but for a reason.  The Coda servers are
> stateful and protect clients from seeing bad data.  The protocol is that
> of callback promises, and when a client wants to store a new version,
> servers will first break callbacks at all other clients.  In this way read
> only access to files/directories goes without ever contacting the servers
> provided files are in cache. 
> Before you made the final change on client2 your server called all other
> clients to break the callback (including the client1 that you had
> shutdown). [The servers do this with a multi rpc to limit the total wait
> to a single timeout.] Client1 was no longer on the net, so the server let
> the RPC time out [sending a variety of retransmisions etc].  This is what
> took a minute.

Hmm, isn't it possible to do this asynchronously? 

> Yet, you do have a point: when a client is shut down orderly, we should
> tell all the servers to which we hold about it, so that it destroys state
> in an orderly fashion.

That doesn't help. For my application I need a shorter response time (< 15
sec.) even if the other client crashes. Is it difficult (possible) to patch
the server/rpc2-library and modify the timeout?

Received on 1998-11-29 12:20:45