SQL Server Performance Forum – Threads Archive

Instances of SQL Server in a W2003 Cluster (a/a)

Hey all, as I have read in the site, it looks like when the cluster is configured as active/active (as my current Windows 2003 cluster with MSCS is) there must be 2 instances of SQL server running. "
An Active/Active SQL Server cluster means that SQL Server is running on both nodes of a two-way cluster. Each copy of SQL Server acts independently, and users see two different SQL Servers. If one of the SQL Servers in the cluster should fail, then the failed instance of SQL Server will failover to the remaining server. This means that then both instances of SQL Server will be running on one physical server, instead of two. http://www.sql-server-performance.com/clustering_intro1.asp "
My purpose, though, is to have all the clients see only ONE instance, so that only one virtual server is running on the cluster :: one node running it as the other just keeps alert for possible failover … Is it that possible? Or will I have to install 2 instances running at the same time?
If so, don’t u think that this will affect application connections when the main node failed? Thank u very much in advance … Pep Solà-Niubó

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You can install one instance only, usually called active/passive. Even if you install two or more instances they will still be seperate instances and has nothing to do with eachother, they just reside in the same cluster. If you then deside to let all run on one node or divide them equally among both nodes is up to you. Example 1:
———-
Node1:
Instance1 Node2:
No instance. passive just as failover backup Example 2:
———-
Node1:
Instance1 Node2:
Instance2 Example 3:
———-
Node1:
Instance1
Instance2 Node2:
No instance. passive just as failover backup

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I understand very well, in fact "example 1" is my final purpose, then, when they say "An Active/Active SQL Server cluster means that SQL Server is running on both nodes of a two-way cluster. Each copy of SQL Server acts independently, and users see two different SQL Servers. " they are referring to the SQL Cluster not the MSCS CLUSTER itself, right?
———————— No one travels so high as he who knows not where he is going… {{Oliver Cromwell}}

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For example, during an operating system failure or a planned upgrade, you can configure one failover cluster to fail over to any other node in the failover cluster configuration. In this way, you minimize system downtime, thus providing high server availability.
Satya SKJ
Moderator
http://www.SQL-Server-Performance.Com/forum
This posting is provided “AS IS” with no rights for the sake of knowledge sharing.

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That is correct.

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If that is correct, that means that I can implement a SQL Server cluster ACTIVE/PASSIVE over an ACTIVE/ACTIVE cluster managed by MSCS??
I dont think thats possible …. ———————— No one travels so high as he who knows not where he is going… {{Oliver Cromwell}}

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The term active/active is used when you talk about the resources within an MSCS, not about the MSCS itself. It’s about how you choose to divide the resources among the nodes. If you use resources (say SQL) on only one node you call it active/passive, if you use resources on both nodes you call it active/active. There is no option in MSCS to "set a node as passive or active". If a node is doing work (say for SQL) it’s active, if not it’s passive.

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