As reported here there could be some issues when trying to stsadm backup and restore on the SAME box or should I specifically say ON THE SAME MSDE or SQL instance. What happens is when we take an stsadm backup, the individual list items, documents, etc are backed up including the GUID for that particular item. When we try to restore it back onto the SAME server it is going to complain.
“No content databases are available for restoring this site collection. Create a new content database and then try the restore operation again.”
Typically you will encounter this while testing backups and restores on the same box (single server configuration), however trying it on a different box or a WSS installation that is using a different SQL/MSDE instance will work OK. So for our pilot sake, we can just add a content datbase under the main WSS administration pages. SPS is smart enough to understand which content database to use when there are duplicate GUID.
My goal was to migrate all those WSS sites, http://server/sites/site1 etc into the “SPS Site Directory” area, stsadm worked very well, without issues. Next I will try to move the content databases directly from WMSDE into SQL Server and post results of such operation.