[477] in athena10
Re: Simulating AFS outages with pyhesiodfs
daemon@ATHENA.MIT.EDU (Quentin Smith)
Wed Sep 3 14:34:31 2008
Date: Wed, 3 Sep 2008 14:33:02 -0400 (EDT)
From: Quentin Smith <quentin@MIT.EDU>
To: Jonathan D Reed <jdreed@mit.edu>
cc: athena10@mit.edu
In-Reply-To: <Pine.LNX.4.64L.0809031401100.32734@infinite-loop.mit.edu>
Message-ID: <Pine.LNX.4.64L.0809031431540.11949@vinegar-pot.mit.edu>
MIME-Version: 1.0
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Hi Jonathan,
One question about this - when you say an "AFS outage", are you meaning a
full network outage, as in the Hesiod servers are also unreachable, or are
you just meaning that the AFS server containing the user's locker is
unreachable?
If it's the latter, I don't expect pyHesiodFS to contribute to any
problems.
--Quentin
On Wed, 3 Sep 2008, Jonathan D Reed wrote:
> pyhesiodfs seems to behave slightly better in an AFS outage than afuse did.
> Here is what I encountered:
>
> -If the locker had already been accessed (say, by a successful login), then
> the Failsafe Terminal option will work, but attempts to access other
> directories will fail with "Timed out" errors. Presumably this is due to AFS
> caching, and might eventually fail if enough time elapses.
>
> -Failsafe GNOME just plain doesn't work (it attempts to create the Nautilus
> directories, presumably because it can't read them, and fails)
>
> -If the locker has not already been accessed (say, after a reboot), it hangs
> at the login screen, and eventually asks the user if they want to log in with
> / as their home directory. If you say yes, it eventually presents the GNOME
> background, but just sits there (I gave up after 10 minutes). If you
> attempt to Ctrl-Alt-Bksp out of the situation, X does not respawn. ps shows
> that X and gdmgreeter are defunct processes, but nothing I tried was able to
> cause them to completely die or to respawn X.
>
> However, pyhesiodfs seems to recover from server outages much faster than
> afuse did.
>
> The situation is still pretty much unusuable, though. Rather than try and
> let Ubuntu figure out what's up with the user's homedir, is it worth adding
> code to the login sequence that explicitly checks if a user's homedir is
> available and punts if it isn't?
>
