[Linux-cluster] doubts about using clvm

[Erling Nygaard]

On 1/2/06, carlopmart <carlopmart at gmail.com> wrote:
> Sorry my poor vocabulary :)

No problem. Common mistake :-)
>
> Erling Nygaard wrote:
> > Some nitpicking first :-)
> > There is no such thing as a "GFS server" or "GFS client". The nodes that
> > are mounting a GFS filesystem are usually called "GFS nodes"
> > However, there are indeed "GNBD servers" and "GNBD clients that exports
> > and imports blockdevices.
> >
> > So I understand your setup to be one node (the Ubuntu node) is acting as
> > a GNBD server and exports two disk drives.
>
> Correct.
>
> > And then there are two nodes (the RHEL4 nodes) that acts as GNBD clients
> > and imports the two disk drives.
>
> Correct.
>   On these disk drives is the GFS filesystem.
>
> No, these are raw partiitons as describres in sources.redhat.com
> (min-gfs.txt).

Oh. Well, these are the partitions you intend to make GFS on then :-)

> >
> > I have not used CLVM with GFS yet, but with the old pool-driver (the
> > volume manager that was shipped with GFS previously) this setup could be
> > done in 2 different ways:
> > 1. Combine the two disk drives on the GNBD server and export _one_ volume
> In this case I need to run clvm on ubuntu server, right??
>
Yes. In this case clvm daemon runs on the ubuntu server. There is one
GNBD server exports the one LVM volume.

In your setup I think this would be the easier way to do the setup.
Your two disk drives will be combined on the GNBD server, so there is
only one volume to be exported by the GNBD server.
So on the GNBD clients you don't have to worry about having to combine
two GNBD imports.

With the second method you would have to run CLVM on both GFND clients
(GFS nodes) to combine the exported disk drives.

Other than somewhat simpler setup I don't thin there is any good
reason for one over the other.

As I said, I have only done this with pool, not CLVM. Other speak up
if this for some bizarre reason would not work.


> > 2. Export _two_ volumes from the GNBD server and combine the volumes on
> > the GNBD client / GFS nodes.
> >
> > I would assume both ways would work with CLVM.
> >
> >
> > On 1/2/06, *carlopmart* <carlopmart at gmail.com
> > <mailto:carlopmart at gmail.com>> wrote:
> >
> >     Hi all,
> >
> >       I am testing Cluster/GFS suite under my vmware lab. I have installed
> >     two RHEL 4 with CS and GFS support. Another machine acts as a GFS
> >     server (Ubuntu breezy server that has rhcs/gfs included).
> >
> >       Ubuntu server has two phisycal disks exported by gnbd daemon and
> >     RHEL   import these disks as a GFS clients. But I would like to export
> >     these disks as a unique disk using LVM. Then, I need to start clvm
> >     process under Ubuntu server or on RHEL clients??? Is it possible to
> >     accomplish this?.
> >
> >     Thanks.
> >     --
> >     CL Martinez
> >     carlopmart {at} gmail {d0t} com

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