A smooth upgrade requires a good plan. Before you upgrade, you need to prepare your environment. The pre-upgrade tasks include the following:
• Ensure the server hardware that will host SQL Server 2008 will be sufficient. The server hardware should meet the minimum hardware requirements, such as the amount of available RAM and disk space. The operating system on the server hardware should also contain the latest service pack or the minimum service pack required by SQL Server 2008.
• Inventory the applications that will use the upgraded server. This list will be used to validate that your upgrade was successful. After upgrade, run through the list and verify that all the applications work correctly, if possible.
• Take note of the cross-edition upgrade matrix. Some upgrade scenarios, like upgrading from SQL Server 2005 Enterprise Edition to SQL Server 2008 Standard Edition, are not supported with an in-place upgrade. SQL Server Books Online describes various upgrade scenarios in an article titled “Version and Edition Upgrades.”
• Take performance benchmarks. In some situations, upgrading may actually decrease query performance. This is usually observed when upgrading from SQL Server 2000, since the query processor internal to the database engine was rewritten in SQL Server 2005. This rewrite causes a different query plan to be created from the queries that you issue. The good news is that most of the time, your queries will run better out of the box in SQL Server 2008. In the rare case that you find your queries running worse, it’s possible to save query plans so there will be no surprises after you upgrade
• Use the Upgrade Advisor tool. Upgrade Advisor is a free, stand-alone application that connects to a SQL Server instance and performs an analysis to determine if any issues need to be addressed before upgrading. It also will analyze script and trace files. Results of this tool should be carefully reviewed and addressed before proceeding with the upgrade.
• Fix or work around backward-compatability issues. The Upgrade Advisor tool will note any backward-compatibility issues. In most cases, when a feature or behavior is changed, Microsoft announces a deprecation of that feature or functionality. This deprecation will last for three releases; in the fourth release, the feature or functionality will be removed from the product. In some rare cases, Microsoft needs to modify or remove a feature without going through the formal deprecation procedure. Thus, if you used this feature and then upgraded, it’s possible that your application would not work as you expected. It is important to address these backward-compatibility issues before upgrading your SQL Server instance.
• Create a back-out plan. If you have done your homework, the upgrade experience should go seamlessly. In the event of something going wrong during the upgrade, you may need to revert back to your original system configuration. This may involve more steps than just canceling the setup wizard. For this reason, it is good to have a formal back-out plan.
• Understand upgrade or migration for each component within SQL Server. When performing an upgrade of a database, most people tend to think about just the relational data. If all you are using SQL Server for is to store relational data, then either using the setup wizard to perform an in-place upgrade or migrating the data using a backup/restore or a detach/attach technique might be sufficient. However, if you use other technologies, you may need to be aware of other issues.
The last item is particularly important, because different components may have different upgrade paths. For example, if you’re using Analysis Services, with an in-place upgrade, you can use the setup wizard just as you would with upgrading the database engine. To perform a migration, you can use the Migration Wizard tool available from the server node context menu off of an analysis server connection in SQL Server Management Studio. If you have Analysis Services projects written using Business Intelligence Development Studio (BIDS), you can simply import into BIDS in SQL Server 2008.
With another component within the SQL Server product, Reporting Services, the migration process is slightly different. Again, if you choose to perform an in-place upgrade, the setup wizard will perform most of the heavy lifting. If you choose to migrate, there is a list of things to do. SQL Server Books Online describes the migration of Reporting Services very well in an article entitled “How to: Migrate a Reporting Services Installation.” As you can see, it is imperative to consider all the components that you are using within the SQL Server product.
Source of Information : Apress Accelerated SQL Server 2008
• Ensure the server hardware that will host SQL Server 2008 will be sufficient. The server hardware should meet the minimum hardware requirements, such as the amount of available RAM and disk space. The operating system on the server hardware should also contain the latest service pack or the minimum service pack required by SQL Server 2008.
• Inventory the applications that will use the upgraded server. This list will be used to validate that your upgrade was successful. After upgrade, run through the list and verify that all the applications work correctly, if possible.
• Take note of the cross-edition upgrade matrix. Some upgrade scenarios, like upgrading from SQL Server 2005 Enterprise Edition to SQL Server 2008 Standard Edition, are not supported with an in-place upgrade. SQL Server Books Online describes various upgrade scenarios in an article titled “Version and Edition Upgrades.”
• Take performance benchmarks. In some situations, upgrading may actually decrease query performance. This is usually observed when upgrading from SQL Server 2000, since the query processor internal to the database engine was rewritten in SQL Server 2005. This rewrite causes a different query plan to be created from the queries that you issue. The good news is that most of the time, your queries will run better out of the box in SQL Server 2008. In the rare case that you find your queries running worse, it’s possible to save query plans so there will be no surprises after you upgrade
• Use the Upgrade Advisor tool. Upgrade Advisor is a free, stand-alone application that connects to a SQL Server instance and performs an analysis to determine if any issues need to be addressed before upgrading. It also will analyze script and trace files. Results of this tool should be carefully reviewed and addressed before proceeding with the upgrade.
• Fix or work around backward-compatability issues. The Upgrade Advisor tool will note any backward-compatibility issues. In most cases, when a feature or behavior is changed, Microsoft announces a deprecation of that feature or functionality. This deprecation will last for three releases; in the fourth release, the feature or functionality will be removed from the product. In some rare cases, Microsoft needs to modify or remove a feature without going through the formal deprecation procedure. Thus, if you used this feature and then upgraded, it’s possible that your application would not work as you expected. It is important to address these backward-compatibility issues before upgrading your SQL Server instance.
• Create a back-out plan. If you have done your homework, the upgrade experience should go seamlessly. In the event of something going wrong during the upgrade, you may need to revert back to your original system configuration. This may involve more steps than just canceling the setup wizard. For this reason, it is good to have a formal back-out plan.
• Understand upgrade or migration for each component within SQL Server. When performing an upgrade of a database, most people tend to think about just the relational data. If all you are using SQL Server for is to store relational data, then either using the setup wizard to perform an in-place upgrade or migrating the data using a backup/restore or a detach/attach technique might be sufficient. However, if you use other technologies, you may need to be aware of other issues.
The last item is particularly important, because different components may have different upgrade paths. For example, if you’re using Analysis Services, with an in-place upgrade, you can use the setup wizard just as you would with upgrading the database engine. To perform a migration, you can use the Migration Wizard tool available from the server node context menu off of an analysis server connection in SQL Server Management Studio. If you have Analysis Services projects written using Business Intelligence Development Studio (BIDS), you can simply import into BIDS in SQL Server 2008.
With another component within the SQL Server product, Reporting Services, the migration process is slightly different. Again, if you choose to perform an in-place upgrade, the setup wizard will perform most of the heavy lifting. If you choose to migrate, there is a list of things to do. SQL Server Books Online describes the migration of Reporting Services very well in an article entitled “How to: Migrate a Reporting Services Installation.” As you can see, it is imperative to consider all the components that you are using within the SQL Server product.
Source of Information : Apress Accelerated SQL Server 2008
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