[OpenAFS] Cache Consistency problem

[Burcin Erocal]

On Thu, 19 Dec 2002 10:46:12 -0500 (EST)
Craig_Everhart@transarc.com wrote:

> AFS (and OpenAFS) provides open/close consistency, not read/write
> consistency.  After a file is written and closed, a new open() on any
> client will see the fresh data.  The mechanism in use here is the
> callback that Paul Blackburn mentioned.  The problem is likely that
> the web server is caching the opens on the files that it is serving,
> so it is not seeing (serving) the fresh data.  If the web server
> shares a client cache with the updater, they both will see the same
> data, as you noticed.  So basically the web server is keeping a cache
> of open files that is overriding the usual AFS mechanism for
> automatically noticing the fresh data.  By contrast, DCE/DFS provides
> read/write consistency, so after a write() completes, a read() on any
> client retrieves fresh data.

When you say "the web server is caching the opens on the files that it
is serving", do you mean apache caching these, or a lower level
mechanism (i.e. in the kernel)?

Accessing the same files with another process on the machine doesn't see
the changes either, so if you mean apache caching then that isn't the
cause.

Thanks
Burcin