[OpenAFS] Disconnected OpenAFS

[Jeffrey Altman]

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shivers@ccs.neu.edu wrote:
> I am someone who would *love* to have an AFS with support for coda-like
> disconnected operation, so that I could use AFS to provide transparent
> access to my data from my notebook & office computer. (Coda won't do; even
> in 2007, it is unusably flaky.)
> 
> A while back, I saw on the Open AFS web page a comment that disconnected AFS
> would be available third or fourth quarter 2007. So I thought I'd ping this
> list, it now being September, to see what the likelihood of this was. Does
> anyone know the status of disconnected AFS? Is it happening?
>     -Olin

Some work has been done on integrating UNIX read-only disconnected mode
onto the CVS HEAD.  On Windows work has been done to ensure that
directories which were actively in use when a machine was disconnected
from a particular volume will continue to be usable until the volume
returns.

The hard part about disconnected operation is not what happens in the
cache manager but the user interface that must go with it so that users
can determine what data should be available in the cache when the client
goes off-line and how collisions should be resolved when the client is
back on-line and the data on the server has been changed.

There are also issues surrounding file locks that must be resolved.  If
the client is disconnected and issues fake locks to an application and
the client then shifts to connected state and the locks cannot be
obtained from the file server, what should happen?

 * Should the file handle be invalidated which might lead to an
   application crash?

 * Should the cache manager refuse to shift to connected mode?

 * Should the cache manager continue to fake the lock and risk data
   corruption?

There is quite a bit more that needs to be done.

Jeffrey Altman

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