[cgl_discussion] Re: [Clusters_sig] A couple of questions

Lars Marowsky-Bree lmb at suse.de
Wed Jan 19 13:34:19 PST 2005

On 2005-01-19T09:12:16, John Cherry <cherry at osdl.org> wrote:

> > Yes, both Linux HA and the (alas, proprietary) OES Novell Clustering
> > Services do support EVMS in cluster mode. The later one for up to 32
> > nodes, I'm told.
> I was only addressing the open source solutions and I have only seen a
> data sheet for the OES Novell Cluster Services.  They claim "integration
> between the cluster volume broker and EVMS".


> BTW, the data sheet for Linux HA says that Linux-HA has no special
> shared disk requirements.  There is no mention of EVMS anywhere on the
> project site.

True, because EVMS integrates with heartbeat and not the other way
around ;-) C-EVMS2 has a plugin to connect to heartbeat. See

> However, services such as a distributed lock manager and/or cluster
> messaging could be considered to be common cluster services that would
> enable the management and coordination of shared resources.  Wouldn't it
> be great if these services were just part of a standard Linux
> kernel?  :)

Indeed ;-)

> > > SW Rolling Upgrades
> > > 	OpenAIS - ??
> > > 	Linux-ha - ??
> > Rolling upgrades and updates are supported with Linux HA for the cluster
> > software itself.
> Yes.  This seems to be the definition of rolling upgrades nowadays.
> True SW Rolling Upgrades is a system software stack issue...not to
> mention data consistency issues.

Yes, for a _true and complete_ rolling upgrade of a cluster node, all
layers of the system have to support it. We just supply a building block
for it.

    Lars Marowsky-Brée <lmb at suse.de>

High Availability & Clustering
SUSE Labs, Research and Development
SUSE LINUX Products GmbH - A Novell Business

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