It's recommended that the SQL Server 2000 machine where SQL Server 2005 will be installed has at least Service Pack 3a, or better yet SP4.
When installing SQL Server 2005 on the same machine as SQL 2000, you might have the following issues:
1. A default SQL Server 2000 instance was not recognized by the installation wizard. The installation could not identify the default SQL Server 2000 instance and therefore it may be asked to install a default 2005 instance. The installation completes successfully, but the new 2005 instance is not really installed. When this happens, you have to uninstall and reinstall the 2005 instance. In the new installation, enter a named instance.
2. The SQL Server 2000 Agent could not restart. After completing the installation, there's a chance the SQL Server 2000 Agent may not restart. Generally re-entering the password in the Agent's Service solves the problem.
3. Enterprise Manager )2000) is not working after the 2005 installation (database servers are running). If the Enterprise Manager is not working after you install 2005, take a look at these steps copied from Microsoft's Co-exist of SQL Server 2000 and SQL 2005:
|Click Start, click Run, type regedit, and then click OK.|
|2.||Locate the following registry subkey:
HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Microsoft SQL Server\80\Tools\ClientSetup
|3.||Right-click the ClientSetup registry subkey, point to New, and then click String Value.|
|4.||Rename the registry subkey that you just created SqlPath, and then press ENTER.|
|5.||Double-click the SqlPath registry subkey, and then type C:\Program Files\Microsoft SQL Server\80\Tools in the Value data box.|
|6.||Click OK, and then close Registry Editor.|
|7.||Click Start, click Run, type regsvr32 "C:\Program Files\Microsoft SQL Server\80\Tools\Binn\sqlmmc.dll", and then click OK.|
4. SQL Server Management Studio is not installed. You need to install .NET 2.0 framework prior to the installation.
SQL 2000 and 2005 can co-exist on the same machine. But here are some issues I've been asked about in the past concerning the interaction between the two versions:
|#||Issue||Error message when using 2005 tools||Error message when using 2000 tools||Possible?|
|1.||New SQL Server Registration||(Success)||A connection could not be established to Server 2005.
Reason: [SQL-DMO]You must use SQL Server 2005 management tools to connect to this server
|Only from 2005 to 2000|
|2.||Multi Server Administration||2005 – master, 2000 - target:
The master server <2005 Server> version 9.00.2047.00 is not compatible with the target server '<2000 Server> version ...
|2000 – master, 2005 - target:
SQL Server registration failed because of the connection failure displayed below...
[SQL-DMO]You must use SQL Server 2005 management tools to connect to this server
|3.||Replication||(Success)||No error message, the SQL Server 2005 instance does not appear in the list of possible subscribers||Only from 2005 to 2000|
|5.||Database restore||Backup – 2005, Restore – 2000:
The backed-up database has on-disk structure version 611. The server suppors version 539 and cannot restore or upgrade this database. RESTORE DATABASE is terminating abnormally.
|Backup – 2000, Restore – 2005:
|Only from 2000 to 2005|
|6.||Log Shipping||'Secondary Server Name' is not a valid secondary server instance because it is not the correct version. Secondary server instances must be servers running SQL Server 2005 or later.||SQL Server 2005 instances do not appear in the list of the possible Secondary instances||NO|
Part 1: Installing SQL Server 2005 on a SQL 2000 machine
Part 2: SQL Server 2000 and 2005: Six compatibility concerns
ABOUT THE AUTHOR
Michelle Gutzait works as a senior database consultant for ITERGY International Inc., an IT consulting firm specializing in the design, implementation, security and support of Microsoft products in the enterprise. Gutzait has been involved in IT for 20 years as a developer, business analyst and database consultant. For the last 10 years, she has worked exclusively with SQL Server. Her skills include SQL Server infrastructure design, database design, performance tuning, security, high availability, VLDBs, replication, T-SQL/packages coding, and more.