Tuesday, March 20, 2012

Quorum Disk or Majority Node?

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?
If you want the quorum locally on each machine, MNS is for you. If you are
ok with the Quorum in one spot, go with the traditional method. In neither
case does it change the requirements for SQL Server Databases to reside on
shared storage.
Cheers,
Rod
MVP - Windows Server - Clustering
http://www.nw-america.com - Clustering Website
http://msmvps.com/clustering - Blog
http://www.clusterhelp.com - Cluster Training
"Kevin Antel" <kevina@.cqlcorp.com> wrote in message
news:um8P7Y5FGHA.208@.tk2msftngp13.phx.gbl...
> 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?
>
|||Is there a "best practice"? Better to have in one spot or two?
"Rodney R. Fournier [MVP]" <rod@.die.spam.die.nw-america.com> wrote in
message news:ul1t%23f5FGHA.1676@.TK2MSFTNGP09.phx.gbl...
> If you want the quorum locally on each machine, MNS is for you. If you are
> ok with the Quorum in one spot, go with the traditional method. In neither
> case does it change the requirements for SQL Server Databases to reside on
> shared storage.
> Cheers,
> Rod
> MVP - Windows Server - Clustering
> http://www.nw-america.com - Clustering Website
> http://msmvps.com/clustering - Blog
> http://www.clusterhelp.com - Cluster Training
> "Kevin Antel" <kevina@.cqlcorp.com> wrote in message
> news:um8P7Y5FGHA.208@.tk2msftngp13.phx.gbl...
>
|||Traditional is the best practice. Very few corporations need MNS. Nothing
wrong with it, just the true need is small.
Cheers,
Rod
MVP - Windows Server - Clustering
http://www.nw-america.com - Clustering Website
http://msmvps.com/clustering - Blog
http://www.clusterhelp.com - Cluster Training
"Kevin Antel" <kevina@.cqlcorp.com> wrote in message
news:OA8fto5FGHA.532@.TK2MSFTNGP15.phx.gbl...
> Is there a "best practice"? Better to have in one spot or two?
>
> "Rodney R. Fournier [MVP]" <rod@.die.spam.die.nw-america.com> wrote in
> message news:ul1t%23f5FGHA.1676@.TK2MSFTNGP09.phx.gbl...
>
|||SQL Server does not support Majority Node Clusters.
Geoff N. Hiten
Senior Database Administrator
Microsoft SQL Server MVP
"Kevin Antel" <kevina@.cqlcorp.com> wrote in message
news:um8P7Y5FGHA.208@.tk2msftngp13.phx.gbl...
> 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?
>
|||I found a very interesting article here :
http://www.microsoft.com/windowsserv...lustergeo.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@.cqlcorp.com> wrote in message
> news:um8P7Y5FGHA.208@.tk2msftngp13.phx.gbl...
>
>
|||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@.discussions.microsoft.com> wrote in message
news:E6E414F7-795A-42A4-9D7E-7AEF21FACEB2@.microsoft.com...
> I found a very interesting article here :
>
http://www.microsoft.com/windowsserv...lustergeo.mspx
> The chapter "Three-Site Majority Node Set Quorum in Geographically
Dispersed
> Clusters to Facilitate Automatic Failover" was the exact solution for some
of[vbcol=seagreen]
> 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:
have[vbcol=seagreen]
versa?[vbcol=seagreen]
|||How about:
SQL Server does not NATIVELY support MNS clustering. Third party add-ons
may alter this behavior.
Geoff N. Hiten
Senior Database Administrator
Microsoft SQL Server MVP
"DAVID A BERMINGHAM" <david.bermingham@.steeleye.nospam.com> wrote in message
news:eKdpQd2JGHA.1132@.TK2MSFTNGP10.phx.gbl...
>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@.discussions.microsoft.com> wrote in message
> news:E6E414F7-795A-42A4-9D7E-7AEF21FACEB2@.microsoft.com...
> http://www.microsoft.com/windowsserv...lustergeo.mspx
> Dispersed
> of
> have
> versa?
>
|||What if for some reason you wanted to do a MNS and all 3 nodes where
attached to the same SAN? Not a good idea, but that would still be a MNS
and it does not require any third party products. No application with any
dynamic data supports MNS without some sort of shared disk, whether iSCSI,
SCSI, SAN or replicated disk.
"Geoff N. Hiten" <SQLCraftsman@.gmail.com> wrote in message
news:eM1JRF3JGHA.1028@.TK2MSFTNGP11.phx.gbl...
> How about:
> SQL Server does not NATIVELY support MNS clustering. Third party add-ons
> may alter this behavior.
> --
> Geoff N. Hiten
> Senior Database Administrator
> Microsoft SQL Server MVP
>
> "DAVID A BERMINGHAM" <david.bermingham@.steeleye.nospam.com> wrote in
message[vbcol=seagreen]
> news:eKdpQd2JGHA.1132@.TK2MSFTNGP10.phx.gbl...
need[vbcol=seagreen]
at[vbcol=seagreen]
is[vbcol=seagreen]
go[vbcol=seagreen]
SteelEye[vbcol=seagreen]
implementing[vbcol=seagreen]
http://www.microsoft.com/windowsserv...lustergeo.mspx[vbcol=seagreen]
anyone
>
|||The solution that interested me was this one :
* Site 1 & Site 2 have hardware replicated storage and are connected via SAN.
* Site 3 is just connected via network and has only local disks.
* 3 nodes are part of the cluster (1 on each site)
* SQLServer instance can be hosted on node 1 or 2 only
* node 3 is only here for Quorum vote (not eligible for SQLServer instance)
Is that possible without 3rd party software ?
If you can explain me quickly why or why not, i would really appreciate (the
whitepaper is not very explicit) !
Thanks.
Guillaume.
=====================================
"DAVID A BERMINGHAM" wrote:

> What if for some reason you wanted to do a MNS and all 3 nodes where
> attached to the same SAN? Not a good idea, but that would still be a MNS
> and it does not require any third party products. No application with any
> dynamic data supports MNS without some sort of shared disk, whether iSCSI,
> SCSI, SAN or replicated disk.
> "Geoff N. Hiten" <SQLCraftsman@.gmail.com> wrote in message
> news:eM1JRF3JGHA.1028@.TK2MSFTNGP11.phx.gbl...
> message
> need
> at
> is
> go
> SteelEye
> implementing
> http://www.microsoft.com/windowsserv...lustergeo.mspx
> anyone
>
>

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