Working with Multiple Versions and Instances of SQL Server

SQL Server supports multiple instances of the Database Engine, Analysis Services, and Reporting Services on the same computer. You can also upgrade earlier versions of SQL Server, or install SQL Server on a computer where earlier SQL Server versions are already installed. For supported upgrade scenarios, see Version and Edition Upgrades.

Using SQL Server Side-By-Side with Previous Versions of SQL Server

You can install SQL Server on a computer that is already running instances of an earlier SQL Server version. If a default instance already exists on the computer, SQL Server must be installed as a named instance. Be aware that there are special considerations while using SQL Server 2008 R2 and SQL Server 2008 side-by-side. For more information, see Considerations for Side-by-Side Instances of SQL Server 2008 R2 and SQL Server 2008. The considerations may also apply in situations where there was a previously existing SQL Server 2008 R2 installation on the machine.

The following table shows side-by-side support for SQL Server 2008 R2:

Existing instance of SQL Server 2008 R2

Side-by-side support

SQL Server 2008 R2 (32-bit)

SQL Server 2000 (32-bit)

SQL Server 2000 (64-bit) x64

SQL Server 2005 (32-bit)

SQL Server 2005 (64-bit) x64

SQL Server 2008 (32-bit)

SQL Server 2008 (64-bit) x64

SQL Server 2008 R2 (32-bit)

SQL Server 2008 R2 (64-bit) x64

SQL Server 2008 R2 (64-bit) IA64

SQL Server 2005 (64-bit) IA64

SQL Server 2008 (64-bit) IA64

SQL Server 2008 R2 (64-bit) IA64

SQL Server 2008 R2 (64-bit) x64

SQL Server 2000 (32-bit)

SQL Server 2000 (64-bit) x64

SQL Server 2005 (32-bit)

SQL Server 2005 (64-bit) x64

SQL Server 2008 (32-bit)

SQL Server 2008 (64-bit) x64

SQL Server 2008 R2 (32-bit)

SQL Server 2008 R2 (64-bit) x64

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Preventing IP Address Conflicts

When a SQL Server Failover Cluster Instance is installed side-by-side with a standalone instance of the SQL Server Database Engine, take care to avoid TCP port number conflicts on the IP addresses. Conflicts usually occur when two instances of the Database Engine are both configured to use the default TCP port (1433). To avoid conflicts, configure one instance to use a non-default fixed port. Configuring a fixed port is usually easiest on the standalone instance. Configuring the Database Engine to use different ports will prevent an unexpected IP Address/TCP port conflict that blocks an instance startup when a SQL Server Failover Cluster Instance fails to the standby node