Coda File System

Re: Network-wide compatibilty of Coda?

From: Ivan Popov <>
Date: Mon, 19 Dec 2005 17:53:41 +0100

On Mon, Dec 19, 2005 at 04:30:55PM +0300, mkondrin wrote:
> question about compatibility of different coda-clients. Say a have a 
> network of coda-clients. Could I upgrade just one of them (suppose all 
> of them as well as servers have 6.0.x version) to the latest version and 
> not touch the rest? Is this safe? Or have I to upgrade the whole network?

Coda is a global file system with all positive and negative consequences.
It is not the software version which is important for interoperability between
a certain client and a certain realm, but the network protocol version
each of them uses.

That means that incompatible changes in the protocol lead to upgrades
all over the world, both client and servers. Fortunately, in most cases
it can be done in two steps, say upgrading clients so that they can talk
to both "old" and "new" servers and then servers. Later on, the backward
compatibility on the client side can be dropped.

In some cases a gradual change is impossible, then the client administrator
would want to update the clients at the same time as the realms the users care
about upgrade their servers.

Evidently, it is impossible, as different Coda realms will upgrade their
servers at different times and for some users it will lead to trouble.
There is no central authority deciding over all Coda servers and clients.

That is why Coda developers are very cautious with doing changes and usually
you should not have to worry about upgrading a single client.
On the other side, you want all your servers and clients to be reasonably
up-to-date, to maintain compatibility with the rest of the world.

Hope it helps,
Received on 2005-12-19 11:54:50