When use sharepoint desinger to  back up , restore  or migrate sharepoint site collections,  contents may be lost . The following is a good solution.

 ”C:\Program Files\Common Files\Microsoft Shared\web server extensions\12\BIN\stsadm.exe” -o export -url http://mydomain1/sites/mysite1  -filename C:\mypath\all.dat -overwrite -includeusersecurity -versions 4

 ”C:\Program Files\Common Files\Microsoft Shared\web server extensions\12\BIN\stsadm.exe”  -o deletesite -url http://mydomain2/sites/mysite2

“C:\Program Files\Common Files\Microsoft Shared\web server extensions\12\BIN\stsadm.exe” -o createsite -url http://mydomain2/sites/mysite2   -ownerlogin administrator -owneremail yongru.zhang@utoronto.ca

“C:\Program Files\Common Files\Microsoft Shared\web server extensions\12\BIN\stsadm.exe” -o import -url http://mydomain2/sites/mysite2  -filename C:\david\sharepoint\all.dat -includeusersecurity