Ok from some refreshing I guess I'll make another iSCSI lun and target on the QNAP and (with thin provisioning I can have 2x 4TB luns on a 4TB array so long as the total amount of actual data stored isn't more than 4TB)
And let my server spend the night moving files from one lun to the other.
I wanted to be sure that it was the issue before doing that though
Ya but any way to check what it is after the fact? I've found the info on how, so I'll do that first.
And set it to 4k because that's what the cool kids are doing j/k but really because it'll mean that I won't have to worry about it as at 4k it's move the limit to 16TB and even if I put 4x 4TB drives in (the max that current drive availability would allow) with raid 5 I still wouldn't hit 16TB with this unit.