Here is my situation. $WORK has a trio of three clustered database servers (64-bit Server 2003) that are currently running two SQL Server instances. Unfortunately, when the cluster was set up a couple years ago my organization did not have 64-bit SQL Server licenses, so we installed the 32-bit version of SQL Server 2005 Enterprise for both instances. They have been running fine, and we're not encountering any limitations of 32-bit SQL Server, so I had not intended to move to 64-bit SQL Server until the hardware (servers as well as SAN) is replaced in about another year. Until I was told that our CMS managers want to move to SharePoint 2010, which requires 64-bit SQL Server 2008; now I need to upgrade much sooner.
I have a plan:
The first instance is a default instance hosting about a dozen miscellaneous application databases. I do not intend to modify this instance at all. In other words, the default instance will remain online throughout the upgrade, and will remain on 32-bit SQL Server 2005, with only a couple of short disruptions due to failovers caused by work on the other instance.
The second instance is a named instance exclusively for our SharePoint installation. I intend to move this to 64-bit SQL Server 2008 R2 Enterprise. Since in-place upgrading is not available when moving from 32-bit to 64-bit SQL Server, I believe I will need to completely uninstall the current named instance from the cluster (taking full backups first, of course), then reinstall a new 64-bit SQL Server 2008 instance with the same name as the previous instance. I will then restore the old databases from backup.
And I have some questions:
Is the above plan reasonable? Any glaring misconceptions on my part? Is there an easier way to do this?
There is no available space on the SAN, so I cannot set up a third instance and migrate the databases over to it (my preferred method). As far as I can tell, a complete reinstall is necessary in this case. Correct?
Will there be any issues running one 32-bit SQL Server 2005 instance on the same cluster alongside a 64-bit SQL Server 2008 instance?
Will installing a new named instance with the same name as the previous named instance cause any trouble?