Spungun

Hi, I've just installed a new server to share the load with existing servers. I'm trying to use Ranger Migrate to transfer user data to new server. I'm copying a year group at a time. Problem I have is ranger migrate stops before transfering the data and says "not enough space on target", although there is 380Gb un-used space. I'm sure I'm missing something simple!!! Any comments would be great, Cheers Mark