[Cluster-devel] [DLM PATCH] DLM: Don't wait for resource library lookups if NOLOOKUP is specified

[Bob Peterson <rpeterso@redhat.com>]

----- Original Message -----
> Hi,
> 
> I think we need to do some more investigation here... how long do the
> lookups take? If the issue is just to create a list of perferred rgrps
> for each node, then there are various ways in which we might do that.
> That is not to say that this isn't a good way to do it, but I think we
> should try to understand the timings here first and make sure that we
> are solving the right problem,
> 
> Steve.

Hi,

Contrary to my previous findings (which I think I may have screwed up),
I've done further investigation and found that the DLM lookups aren't the
issue at all. Also, making the DLM master the lookup node doesn't seem to
make much difference either. So I'm scrapping this dlm patch.

My latest set of patches now includes one that evenly distributes a
preferred set of rgrps to each node. Unlike Dave's original algorithm in
GFS1, this is a round-robin scheme that makes every node "prefer" every
Nth rgrp, where N is the number of nodes. This seems to be just as fast
if not faster than messing around with DLM.

Hopefully I'll be posting more patches in the near future. I'm currently
running some more tests regarding minimum reservations, and I'll post
patches depending on those results.

Regards,

Bob Peterson
Red Hat File Systems