what is the best way to copy database from overseas?

Hello All,

As customer need to migrate their databases(200 databases) to our data center, at this moment, we usually ask customer to send full backup by HDD and then send trn files via FTP, then we restore full backup and apply latest trn files until cutover. However FTP is not stable, trn files are always broken.

The databases size are 3GB~150GB, trn file size are 1MB to 5GB, especially the big trn files are failed every time, we have set transfer mode to Binary in FTP client, but it still fails.

I have VPN access to their database server, so in this case is there a better way to copy/migrate their databases to our server?

Customer using Windows 2003 + SqlServer 2008

We using Windows 2012 R2 + SqlServer 2014

Appreciate your suggestions/advises.

Thanks,

Albert