[Linux-cluster] ext3 filesystem

[Herta Van den Eynde]

On 14/12/06, Robert Peterson <rpeterso at redhat.com> wrote:
> David J. Otis wrote:
> > Is it possible to have an ext3 filesystem mixed with the gfs
> > filesystems on my SAN that can be mounted by all nodes?
> Hi David,
>
> As long as the ext3 file system is mounted read only by all but one
> node, you should be able to do this.
> However, if you need read/write capabilities on both file systems on the
> SAN, then ext3
> will just get you in trouble.  Since ext3 isn't cluster aware, the nodes
> will walk all over each other's data.
> That's what GFS was designed to prevent.
>
> Regards,
>
> Bob Peterson
> Red Hat Cluster Suite
>

What good is mounting the ext3 filesystem read-only on all but one node?
Suppose node A is the node that mounts the filesystem read-write, and
node B a node that mounts it read-only.  B reads a file from the
filesystem, which gets cached on node B.  Node A changes that same
file.  How is node B to know that the data it cached is out of date?

Kind regard,

Herta