[OpenAFS] OpenAFS - Transarc compatibility

[Derrick J Brashear]

On Sun, 29 Jul 2001, Charles Karney wrote:

> I recall reading a commitment that OpenAFS and Transarc will remain "wire"
> compatible.  I take this to mean and a mixed
> 
>     {OpenAFS,Transarc}/{client,server}
> 
> works.

That's the intent.

> I'm also interested in understanding whether this compatibility extends to
> switching between OpenAFS and Transarc on a client or a server (on a given
> platform).  This will inevitably come up as people transition from Transarc
> to OpenAFS.
>
> On the client side this would mean two things:
> 
> * does running a Transarc command (e.g., fs) on an OpenAFS client work and
>   vice-versa?

The problems in this vein will arise if and when IBM begins adding new
pioctls if they don't skip pioctls which have since been allocated;
There's still no official buy-in to a central resource registry. For now
it works, and we hope to keep it that way.

> * are the contents of the cache meaningful when switching systems?

Currently yes. Soon no, but it means effectively you lose your cached data
when you switch, and nothing else. Do you plan to switch back and forth
frequently?

> On the server side this means that the following would need to be
> interchangeable:
> 
> * the files in /usr/afs/db;

yes

> * the contents of /usr/afs/etc;

yes

> * the server partitions /vicepa;

yes (unless they introduce a new iopen fileserver port somewhere we can't
figure out what they end up doing, but that's future work)

> * AFS backups tapes;

yes

> * AFS backup configuration files (tapeconfig, CFG_*);

yes

> * the format of vos dump/vos restore.

yes

> I suspect that the current answers to these questions is probably yes, but
> that this may not always remain true in the future.

If something is going to change in an incompatible way you can be assured
that you'll see discussion first.