Cluster Fail Over

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Guest

Hi,
Here is my situation (Maybe someone can help.)

I have 2 Win2k Adv servers SP4 in a cluster with 2 groups: Cluster group and
DB group[Oracle group].
I have been testing cluster performance and fail over as follows:
Test1:
1) Both groups resides on 1 node [N1].
2) From within cluster admin UI I have opened Cluster group, selected Quorum
drive, right click, and selected the Initiate Failure. At the 4th time
Cluster group failed over BUT the DB group failed over as well. Cluster
service was recycled.
Test2:
3) Each group resides on different node.
4) Initiating failure will fail only the group which resource was
initialized as failure.

Question\Problem: In case where all groups reside on one node [Test 1] why
does DB group Fail Over when we initiate a failure on the Cluster group
quorum drive Only?

Thanks. IS.
 
Hi there,

When you initiate the failure on the quorum disk, you would affect the functionality of the cluster itself.
Quorum being the central location where your cluster resource arbitrations being determined, has to be online all the time. If you initiate a failure of that quorum disk, that node would "think" that it has
problem communicating with that important resouce. Thus to avoid any possible problem, it too initiate the failure of any resources that it has on that node. This caused the failover of your DB
group.

Here is a good explaination of Quorum:
The quorum resource plays a crucial role in the operation of the cluster. In every cluster, a single resource is designated as the quorum resource. A quorum resource can be any resource with the
following functionality:


- It offers a means of persistent arbitration. Persistent arbitration
means that the quorum resource must allow a single node to gain
physical control of the node and defend its control. For example, Small
Computer System Interface (SCSI) disks can use "Reserve and Release"
commands for persistent arbitration.

- It provides physical storage that can be accessed by any node in the
cluster. The quorum resource stores data that is critical to recovery
after there is a communication failure between cluster nodes.


On the other hand, if you initiate a failure of other disk than the quorum, this should not cause the quorum disk to failover.

As a test I would suggest that you do a move group instead.

Some good articles for this would be:
Failover/Failback Policies on Microsoft Cluster Server
http://support.microsoft.com/default.aspx?scid=kb;en-us;197047

Quorum Drive Configuration Information
http://support.microsoft.com/default.aspx?scid=kb;en-us;280345


I hope this clarify the confusion.

Thank you,

Alex Chandra [MSFT]
Microsoft Corp.

--

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Hi,
Here is my situation (Maybe someone can help.)

I have 2 Win2k Adv servers SP4 in a cluster with 2 groups: Cluster group and
DB group[Oracle group].
I have been testing cluster performance and fail over as follows:
Test1:
1) Both groups resides on 1 node [N1].
2) From within cluster admin UI I have opened Cluster group, selected Quorum
drive, right click, and selected the Initiate Failure. At the 4th time
Cluster group failed over BUT the DB group failed over as well. Cluster
service was recycled.
Test2:
3) Each group resides on different node.
4) Initiating failure will fail only the group which resource was
initialized as failure.

Question\Problem: In case where all groups reside on one node [Test 1] why
does DB group Fail Over when we initiate a failure on the Cluster group
quorum drive Only?

Thanks. IS.
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