[Linux-cluster] newbie: gfs merge

[Bowie Bailey]

wolfgang pauli wrote:
> 
> I installed gfs and all the cluster stuff on our systems and I didn't
> have the impression that I missed any of the steps in the manual. So
> I have to nodes which both have a gfs partition mounted. I can also
> mount these, if I exported them with gnbd. But I don't see the big
> difference to nfs yet (apart from maybe performance). I thought that
> if I name the gfs-partitions the same (clustername:gfs1) they would
> be magically merged or something like that. I thought this was meant
> by the notion in the docs that GFS does not have a single point of
> failure. Or that we could have redundant file-servers. What did I get
> wrong about all that? 

It sounds like you are a bit confused about what GFS does.  I replied
to someone within the last week or so on almost the same issue.  Check
the archives.

GFS is a filesystem that allows multiple nodes to access and update it
at the same time.  The cluster services manage the nodes and try to
prevent a misbehaving node from corrupting the filesystem.

If you have hard drives in all of your nodes, GFS and the cluster will
not help you make them into one big shared storage area -- at least not
yet, I believe there is a beta (alpha?) project out there somewhere.
If you have a big storage area, GFS and the cluster _will_ allow you
to connect all of your nodes to it.

The redundancy comes in the fact that you have multiple machines
running from the same storage area.  If one of the machines goes down,
the others can continue working.  In a load-balanced configuration,
the loss of one of the nodes will be transparent to the users.  In
theory, of course...  If the storage dies, that's another issue.
Hopefully, your storage is raid and can handle a disk failure.

-- 
Bowie