You can take measures to reduce the downtime caused by upgrade of the MS SQL Server database. The downtime involved depends on the release you are upgrading to. For example, the upgrade from version 7 to 8 is fast.
You can find more information on upgrading the SQL Server database on SAP Service Marketplace at:
service.sap.com/instguides ® Other Documentation ® Database Upgrades
1. You read the upgrade documentation.
This helps to avoid unexpected problems during the upgrade.
2. You plan the upgrade carefully.
Rather than simply starting the upgrade and hoping for the best, plan the procedures involved in advance. Make sure that all the resources (that is, people and equipment) are available.
3. You rehearse the upgrade using a test system.
The best preparation of all is to rehearse the upgrade fully using a test system that is as similar to the production system as possible.
You can now upgrade the database with the minimum possible downtime.