Lustre discuss - Mar 2010 - upgrading lustre 1.6.x to 1.8.x, client or server first?

Hi Everyone,

We are planning an upgrade from 1.6.x to 1.8.x and would like know, 
especially
for the larger sites, which systems people are upgrading first; servers 
or clients.

Lustre is compatible with doing upgrades either way:

upgrade servers to 1.8.x first, then following with clients

OR

upgrade clients to 1.8.x first, then following with servers

I''m guessing the large sites can''t just upgrade everything to
1.8.x at a
single
point in time.  (I know we can''t take that kind of downtime.)

So what are the larger sites doing and more importantly, why are you 
doing it
that way?

Thanks,

jdk