[Linux-cluster] GFS2 and lvm

[Steven Whitehouse]

Hi,

On Mon, 2010-02-15 at 13:33 -0800, Scooter Morris wrote:
> On 02/15/2010 12:42 PM, Jos Vos wrote:
> > On Mon, Feb 15, 2010 at 01:20:35PM -0500, Mario Salcedo wrote:
> >
> >    
> >> Hi, I am configuring  a Red hat cluster. In the guide say: "A GFS2
> >> file system must be created on an LVM logical volume that is a linear
> >> or mirrored volume". Is that true.
> >>
> >> I create GFS2 without LVM. I think all ok.
> >>      
> > Not really...
> >
> > How do you ensure then that the device paths of the GFS filesystems
> > are the same on all nodes (as is required by the shared cluster.conf)?
> >
> > A shared disk may appear as /dev/sda in one node, but as /dev/sdb on
> > another node, for example, dependent on hardware or configuration
> > details.
> >
> >    
> Actually, this is not really true.  We have many GFS2 filesystems on a 
> three node cluster and we don't use LVM.  It really depends on how you 
> are mounting the filesystems.  You really need to mount them by LABEL, 
> so the underlying disk identifiers becomes irrelevant.
> 
> -- scooter
> 
Any underlying storage system should be ok provided it provides the
guarantees required by GFS2 in terms of caching and ordering of
operations. The reason that the docs mention the use of CLVM is that it
is a requirement for support, not because other solutions (including
direct sharing of disks) will not work,

Steve.