It's usefull to export Site Collection when you need to migrate your site between SharePoint farm, or just to pass from one environment to another envirnment (i.e :dev to QA).

On the source server:

Connect one of your MOSS server and type the following command:

stsadm -o export -URL http://your_site_collection -filename youtpath\your_filename.cab -cabsize 1024 -versions 1

Versions: 1 to 4, 1 for Major Version (default) ; 2 the current version, either the last major or the last minor; 3 Last major and last minor version for files and list items and 4 All versions for files and list items.

If you need to import the security, you can the following switch: -includeusersecurity.

Note:If you want to increase import performance add the following switch: -nofilecompression.

Technical reference: http://technet.microsoft.com/en-us/library/cc262759.aspx

On the target server:

Copy all the cab files from the source server to the target server, create a new web application befor to import the site collection, and type the following command:

stsadm -o import -URL http://your-web_app -filename path_of_your_cab_file_or_folder(nofilecompression only) -updateversions 1 to 3

Updateversions:

  1. Add new versions to the current file (default)

  2. Overwrite the file and all of its versions (delete then insert)

  3. Ignore the file if it exists on the destination

Technical reference: http://technet.microsoft.com/en-us/library/cc261866.aspx