[Lustre-discuss] Lustre attribute caching?

[Daniel Kobras]

Hi!

I wonder about Lustre's client-side caching strategy for file attributes
and directory entries, and whether it suffers from the same problems as
NFS in this regard. I seem to be unable to find this question answered
on the web, so I'd be happy for any hints.

Specifically, I'm interested in caching of negative entries. With
/sharedfs shared via NFS, attribute caching might prevent clientA from
seeing the newly created file in the final stat call of this test:

On clientA:

# rm -f /sharedfs/test; ls -l /sharedfs/test; ssh clientB "touch /sharedfs/test"; stat /sharedfs/test

How does Lustre behave in this case? Are newly created files immediately
visible on all clients, or will they cache (negative) attributes and
dentries for some time? Does Posix mandate specific behaviour in this
regard?

Thanks for any insight,

Daniel.