Jim Starkey wrote:

>
>
> High personal shared files are also a problem. Unless the
> various cluster members are in serious cohoots, it precludes
> disk caching. For high end disks, DEC used unusually bright
> disk controllers that understood clusters. Cheap disk required
> that cluster member emulate cluster controllers with local
> disks. Linux (and most Unixes) would probably take a great
> deal of work to ensure that at the time a process level
> write completes that page can be safely fetched on another
> code on the cluster. A really dumb cluster design would make
> this easy, but would also make the cluster useless.
>

There is work being done on this for Linux.

http://www.globalfilesystem.org/

Emil