[Linux-cluster] partitioning of filesystems in cluster nodes

[Bowie Bailey]

RR wrote:
> Right, it is indeed what I want to do. But now let me understand the
> basics of GFS. GFS actually runs on the SAN but the GFS
> drivers/software that I install on each of my cluster node just
> allows each of these nodes to see these volumes? Something analogous
> to say iscsi-initiators on a node to via the LUNs on an iSCSI SAN? If
> that's true, then is it possible for me to say have my /opt/local
> installed on the GFS managed filesystem on the SAN such that whatever
> application is installed once in this directory can be accessed by
> all  nodes mounting that filesystem? So kind of get install once, use
> everywhere kind of a deal? 

GFS is a filesystem similar to ext3 or xfs.  The only difference is
that it is cluster-aware and can be accessed by multiple nodes at the
same time without data corruption.

The software/hardware that you install on each node to allow it to see
the volumes could be an iscsi initiator or something else depending on
your physical storage.

You can put /opt/local on the GFS and use it like you suggest as long
as all of the programs installed there are self-contained and do not
rely on libraries installed elsewhere than may not be available on all
of the nodes.

Also, let me clarify the LVM/raid thing.  The only limitation is that
you cannot export two partitions from your shared storage and then put
them into a software raid partition.  This is because the software
raid subsystems are not cluster-aware and each node would be trying to
do it's own raid setup which would cause data corruption.  If the
partitions are not part of the shared storage, you can do whatever you
want with them.

-- 
Bowie