Thank you.i didn’t get your point “Now you can’t run a single instance of SQL Server across two nodes of the customer. A single instance can only run on one node of the cluster at any one time”.if u mean Active/Active failover, i am not doing that.
In my case the first active instance(node1) is for sharepoint database and the failover on passive(node2), now i am adding node 3 which needs to be active (will be used for biztalk database) and failover will be again on node2. if i am thinking wrong please correct.
i would be happy if you/anyone could provide me any documentation or links with similar scenario. i still have confusion with how Quorum and shared drive will be accessed.

You install two SQL instances. Both servers will not work on the same instance simultaniously, but you can have each server own an SQL instance; thus, making it active/active.

The failover will not be instant. You will have a few seconds of downtime while the services transfer and come online on another node.

In case you still need an answer… If I understand your question correctly, you have a two node cluster with activepassive node configuration to which you are adding a third node and a new instance of SQL Server thus ending up with node1 = active, node2 = passive and node3 = active…

assuming this is right, the answer about requiring down-time is still a little tricky since pending reboots on any of the nodes will flag the install with an error until you reboot all the affected nodes, but again assuming you are doing this on an inactive node and all cluster nodes are free of those nuances, you might just get away with no downtime at all…

take a look at this article for reference:
How to: Add or Remove Nodes in a SQL Server 2005 Failover Cluster (Setup)
http://msdn.microsoft.com/en-us/library/ms191545%28SQL.90%29.aspx

Also, another one that came in handy was this check list:
http://blogs.msdn.com/b/blakhani/archive/2008/06/09/sql-2005-cluster-setup-checklist.aspx

BTW, do not worry about how the SQL Instance will access the Quorum drive since this is a Windows cluster function; as to how your new instance will become a part of the cluster the answer is you will be prompted to create a new cluster; when you check the box “create a new cluster”, then at some point in the installation you will be asked to enter the name of the virtual server and select to which of the cluster groups you wish to install into.

Hope this helps…

to clear the last part of my earlier post…
When you select “create new cluster”, you are only creating the SQL Instance, which will be hosted on the Windows Cluster…

Hope this helps

Thanks to all . it helped me a lot

Hi Jasina,

Would you mind approving the answer that helped you solve your problem for future IT Knowledge Exchange users who are dealing with the same or similar problem?

Thank you!

Melanie