[OpenAFS] AFS clients for OSX/Darwin

Ben Poliakoff benp@reed.edu
Tue, 25 Apr 2006 12:06:54 -0700

* Jeffrey Altman <jaltman@secure-endpoints.com> [20060424 20:32]:
> Ben Poliakoff wrote:
> > I frequently get "Operation timed out" messages after changing my IP
> > address (most commonly occurs when moving from a wired ethernet to a
> > wireless connection).  These timeout messages *eventually* clear up
> > (usually after three to five minutes) but I don't see these sorts
> > of errors when running the Arla client.
> > 
> > My AFS *servers* are still running 1.2.x code (and I have noticed the
> > 'Mobile clients' paragraph in the release notes for 1.4.1), so perhaps
> > some of this behavior would improve with updates to the servers.  Does
> > this sound like the sort of problem that might be solved by 1.4.1 on the
> > servers?
> > 
> > Ben
> Here is a wild guess.  When you turn off the wired network the AFS
> client marks the servers as "down" and they are not checked for up
> to five minutes to see if they have come up again.  This check of
> down servers occurs every five minutes by a daemon thread.
> On Windows, I watch for notification of network interface changes and
> if there is a change I wait several seconds and then immediately force
> a check of down servers.
> Jeffrey Altman

That certainly sounds like a reasonable hypothesis.  I've created a
small tcpdump transcript of this behavior and posted it here:


The transcript starts just after I've switched from one network
interface to another (wireless to wired in this case).  The transcript
covers the time it took to "cd" into a directory in our AFS cell and to
create a small text file (echo "hithere" > testfile).  The "cd" part
took many tries; after the first lengthy timeout I started getting
immediate "Operation timed out" messages each time I issued the "cd"
command.  Eventually the "cd" command worked and then I was able to
create the file.

The transcript makes it clear that the latency/timeout issue only
persisted for a little more than two minutes (but from an interactive
shell/gui it *feels* longer).

Is there code in the OSX client to look for "notification of network
interface changes"?