[OpenAFS-devel] Re: freezes acessing /afs/.git

[chas williams - CONTRACTOR]

On Fri, 15 Aug 2014 12:06:53 -0400
Jeffrey Hutzelman <jhutz@cmu.edu> wrote:

> Needing an upcall when a real new cell is discovered is a reasonable
> thing.  Needing frequent upcalls because something is walking its way up
> the directory tree looking for magic directories is a different thing.

It's already happening now.  People don't seem to be complaining that
the upcall is slow but rather the DNS searches take too long resolve.

> OK, now, really finally: are there some kludges^Wheuristics we can
> apply?  For example, don't try AFSDB lookups for single-label cell
> names?  Or perhaps some kind of blacklist mechanism?

Immediately, we could stop lookup up names are that known to be invalid
DNS names.  For instance, names including '_' (like DS_Store) should
never be resolved.

As with any black list, it's only as good as the people who configure
it.  Since OpenAFS doesn't typically see much in the way of
configuration on clients past installation, it would necessary to ship
a minimal black list that perhaps wouldn't have much value for most
sites.

This is similar to the cache size problem.  It would be best to
be as automatic as possible.