[CentOS] iSCSI disk preperation

Tue Feb 8 21:46:52 UTC 2011
Dr. Ed Morbius <dredmorbius at gmail.com>

on 09:34 Tue 08 Feb, John Hodrien (J.H.Hodrien at leeds.ac.uk) wrote:
> On Tue, 8 Feb 2011, Dr. Ed Morbius wrote:
> 
> > *OR* as a special case, if access is *only* read-only (or read-only to
> > all but one initiator).
> 
> I get the all read-only case, but wouldn't the read-only clients end
> up caching filesystem data that has since been changed by the
> read-write client?  I'd have thought the read-only initiators would
> get pretty quickly confused.

Good point.  If the data were highly volatile, this would seem to be
likely.  I'm not sure what the consequences of that confusion might be.
This could be an interesting little side-research project.

Infrequent writes, journaled filesystem, minimized caching, while not
entirely kosher might work "well enough" in many cases.  Probably not
what you'd want in a production world though, and NFS read-only shares
would seem a more appropriate solution.

Cache coherence is very, very sticky stuff, and it's what burns a whole
lot of computing operations.

-- 
Dr. Ed Morbius
Chief Scientist                             When you seek unlimited power
Krell Power Systems Unlimited                       Go to Krell!