Apply a service pack or patch SQL Server 2008 in a clustered environment 
    Step 1 : Validation wizard 
    Step 2 : Pre-check
    Step 3 : Installation of the first node
    Step 4 : Add a new node 
    Step 5: Apply a service pack or hotfix on a SQL cluster 

Installing Service Pack SQL Server 2008 in failover cluster is very different than the SQL Server 2005 cluster failover.

With SQL Server 2005, when you start installing cluster service pack (or hotfix), it must be launched on the active node (node that hosts the instance). When installing the Setup will launch simultaneously  "remote silence" on all passive nodes. All nodes in the cluster containing the SQL Server instance are updated in the same time.

With SQL Server 2008, to reduce the downtime, we have revised the method of deployment. Now if you want to apply a service pack (or hotfix), you must install in first on the passive nodes. The passive nodes are updated before the active node.

Therefore, for your instance SQL Server 2008  in failover cluster, you must follow the scenario below for the application of Service Pack, Cumulative Update or Hotfix :

1.  Apply the hotfix on pasive node N2
2.  Reboot the passive node N2
3.  Failover on SQL resource : the passive node become the active node
4.  Apply the hotfix on the passive node N1
5.  Reboot the passive node N1

You can check the version of SQL server with the following query:


      SERVERPROPERTY('IsClustered') as _1_Means_Clustered ,   
SERVERPROPERTY('Edition') as Edition ,   
SERVERPROPERTY('ProductVersion') as Version  , 
SERVERPROPERTY('ComputerNamePhysicalNetBIOS') as ActiveNode


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