Dave:

We have turned off distributed directories in 2.9 due to a race condition
that occurs when a directory splits, which may allow native IB to work, as
long as the initial root information has already been created.  The
loopback messages occur when a directory splits and metadata has to be
updated; with distributed directories turned off, the splits never happen.
The loopback messages also occur when a *NEW*  filesystem is initialized
during server startup time, which happens whether distributed directories
is turned off or not.    So, if you have gotten past the initial startup
successfully, then it is possible that the current IB code will work, but
this IB code is NOT the code we are merging in from our 3rd party.  Also,
even if you think the startup was successful, it is possible that the
metadata databases are still incorrect, which may cause sporadic problems.

Hope this information gives you a little more insight into the problem.

Have a great holiday!

Becky

On Thu, Jul 30, 2015 at 1:25 PM, Dave Love <[email protected]> wrote:

> Becky Ligon <[email protected]> writes:
>
> > Dave:
> >
> > The problem we are working to resolve now involves calling native IB in a
> > loopback fashion.  Under TCP, loopback works fine, but IB doesn't
> > understand loopback, unless you implement it yourself.  In the past, PVFS
> > never used loopback calls; however, when distributed directories was
> > implemented, loopback was used.  At the same time, we are merging IB code
> > written by a 3rd party.  So, between the two, native IB is just not ready
> > yet.  The loopback issues have been resolved and testing of the merged
> code
> > is underway with 2.9.
> >
> > As far as I know, native IB works with 2.8.x.
>
> Thanks for the info.  It's confusing that 2.9 appears to work OK
> intra-node too.  Anyway, I'll try to get some performance figures when I
> get back from holiday.
>
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