Performing a Side-by-Side Upgrade
The side-by-side upgrade is best for site collections larger than 30 GB, and may be required in situations where the upgrade might fail because of disk space issues on the database server.
If you host multiple web applications, as most of us do, the side-by-side upgrade process lets you upgrade web applications one at a time to provide training and ease the transition. You can also upgrade individual site collections within a web application, but since the top-level site must be upgraded first, that scenario seems somewhat rare.
To perform a side-by-side upgrade:
Perform a full backup of the content and configuration databases.
Run PRESCAN.EXE /all. Prescan must succeed without errors for the source web applications to appear in the Site Content Upgrade Status page in Central Administration.
Install WSS 3.0 (SharePoint.exe) on the production server. Choose the Gradual upgrade option during setup (see Figure A-1).
Configure the SharePoint installation to use production database server and email settings.
If using MOSS, install it at this point by running OfficeServer.exe. You must install WSS before installing MOSS when performing an upgrade.
Navigate to the WSS 3.0 Central Administration site and click Operations → "Site content upgrade status" under the Upgrade and Migration heading.
Click the link next to the site to upgrade. SharePoint displays the Set Target Web Application page. Complete the page discussed earlier in "Performing a Trial Upgrade" (refer ...