Shared disks

[Steffen Persvold]

On Thu, 9 May 2002, Jon Hittner wrote:

> Hi,
> Im not sure if what Im trying to do is possible under linux and if so, I
> thought that beowulf might be a posible solution.
>
> I just got a Hitachi 9200 Fibre disk array, and I hooked it up to two
> of my linux servers.  I created a raid set, set it up, and I can mount it
> from both systems fine.  What I want to do is mount the disk rw on one
> system and ro on the other. So the Second system can process data that
> the first one collects.  NFS is much too slow for our use.
>
> What is happening, is that the only way I can see changes I make on the
> other system, is to umount and then remount the ro volume on the second
> system. Until I do that, new files never show up, and deleted ones never
> disapear.  After I remount, then I can access all the files with no
> problem.    I have tried several filesystems (reiserfs,ext2,ext3) and I see
> the same problem.
>
> Am I missing a mount option or something?  Is this even possible? Is there
> anyting in Beowulf that would help?
>

Hi Jon

It's not possible for two (or more) machines to share the same filesystem
without some sort of coherence protocol between the two machines. All the
filesystems you've tested are so called 'local filesystems' which doesn't
have this. What you're looking for is a cluster filesystem such as GFS
(http://www.sistina.com).

Regards,
Steffen