The new version of STSADM even replaces the old Smigrate, which previously was the preferred way of backing up a single site or copying sites between SharePoint servers. The new commands in STSADM are Export for backing up a single site and the Import for restoring the site. Below is a summary of what this new set of commands can do:
It can back up and restore single sites.
It can back up any site including its subsites. It does not have to be the top-level site in the site collection.
It can restore the site permissions (something the old Smigrate could not do).
The result will be stored as a file.
It must be executed on a SharePoint server with a Central Administration tool installed.
You must be the site administrator to run this command.
This is a command line tool. You can schedule it using Windows Tasks.
This is a great tool when you need to make a backup of a single site; for example, when you want to move or copy a site to another SharePoint environment, or to move a site from one site collection to another in the same SharePoint server. In the following example, you will make a backup of a subsite with the URL http://srv1/sitedirectory/it and save the backup file as "it.bak" to the c:\bkup folder. Then you will restore this site to another URL location (http://srv1/sitedirectory/sales/it) and retain the same user permission settings.
Try It Out: Back Up a Single Site with STSADM