Re: Quorum Disk or Majority Node?

I would disagree with Geoff's statement that SQL Server does not support
majority node clusters, unless he can point us to the relevant MS
documentation.  I have many customers doing MNS and SQL server
implementations; as long as you understand the requirements and limitations.

I believe MNS were introduced to facilitate clustering across remote
locations, hence no shared storage.  Obviously, you have to have a
replacement for that shared storage so that the SQL data is available on the
passive node in the event of a failure.  What that means is that you need to
do some sort of replication, usually a third party product such as NSI
DoubleTake for replication.

The other requirement is that a majority of the servers need to be available
in order for a failover to take place.  So that means you need to have at
least 3 nodes in your cluster in order to have a failover, because in a two
node cluster if one node fails you only have one node left, and 1 of 2 is
not a majority.  You need at least 2 out of 3 nodes to have a majority.

In a local cluster where shared storage is available, you will want to go
with the traditional quorum based clustering.  If you have no shared
storage, you will want to go with MNS and data replication.

Alternatively you can ditch MSCS altogether and go with a third party
solution such as LifeKeeper Protection Suite for SQL Server from SteelEye
Technology which is a HA and DR solution combined which eliminates the need
for MSCS, MNS, shared storage and a quorum device.

-- 
DISCLAIMER: I am a SteelEye Engineer with years of experience implementing
HA and DR for WIndows solutions including Exchange and SQL server.


"GNocent" <GNocent@xxxxxxxxxxxxxxxxxxxxxxxxx> wrote in message
news:E6E414F7-795A-42A4-9D7E-7AEF21FACEB2@xxxxxxxxxxxxxxxx
> I found a very interesting article here :
>
http://www.microsoft.com/windowsserver2003/techinfo/overview/clustergeo.mspx
>
> The chapter "Three-Site Majority Node Set Quorum in Geographically
Dispersed
> Clusters to Facilitate Automatic Failover" was the exact solution for some
of
> my split brain problems, so I wanted to try this solution.
>
> Do you mean that it is a non applicable solution with SQLServer ?
> Why ? (I was thinking that the impact was limited to Quorum+MSCS, not
> clustered resources !)
>
> Thanks for your reply.
>
> Guillaume.
>
> =======================
> "Geoff N. Hiten" wrote:
>
> > SQL Server does not support Majority Node Clusters.
> >
> > -- 
> > Geoff N. Hiten
> > Senior Database Administrator
> > Microsoft SQL Server MVP
> >
> >
> >
> > "Kevin Antel" <kevina@xxxxxxxxxxx> wrote in message
> > news:um8P7Y5FGHA.208@xxxxxxxxxxxxxxxxxxxxxxx
> > > New to Windows MCS 2003 is the Majority Node Set option, does anyone
have
> > > any experience where Majority Node is better than Quorum or vica
versa?
> > >
> >
> >
> >


.

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