Poceh, I'm running VMFS5, virtual machine version 10 and I am actually trying to run the conversions to the same ESX host, since the other one's aren't upgraded to 5.5 yet and does not support volumes of this size. This ESX host doesn't have any VMs on it and there's no other load than these conversions. At the moment there's no converter traffic either since I can't get these conversions going. The one server that I managed to get running yesterday failed after an hour.
I read that you can have 52 NFC connections: http://pubs.vmware.com/vsphere-50/index.jsp?topic=%2Fcom.vmware.vddk.pg.doc_50%2FvddkDataStruct.5.5.html
How many connections does one conversion use? Is it more than 1 ?
I also came across the following article:
http://kb.vmware.com/selfservice/microsites/search.do?language=en_US&cmd=displayKC&externalId=1006999
Does that mean when converting a 15 TB server I would actually need 30TB+ on the destination datastore?
I tried to convert with thin disk volumes instead of thick, but no change. Same error msg.