Copy data in iSCSI data file extent to new extent

[Light-fixture]

What is the best way to copy data within an iSCSI data file extent to a new data file extent?

Why?
My first FreeNAS server had 30TB of storage which connects via iSCSI to Windows.
Within Windows, I set formatted the 'drive' with a the cluster size of 8KB - limiting me to a maximum of 32 TB.

My new box has ~72TB. To make things easy (keep the NTFS permissions without effort), I copied my 30TB file from the old server to the new server then connected to the new extent with Windows. When I went to increase the drive size, I got an error and realized cluster size was a problem.

Figuring I require a 16KB sector size (20% free rule for snapshots, etc so I expect a 60TB maximum), I need to move the data within the current extent to the new extent.

Currently
I have 2 copies of my data. One on the old server, one on the new server.

Options
What is the best way to copy the data from one extent to the other?
The option as I see them:
a) Old server to new server (old server has a degraded disk and has 1Gb ethernet)
b) New server to new server

1) Mount the iSCSI extents within Windows, copy to the new extent
2) Mount the iSCSI extents within FreeNAS, copy to the new extent
3) ??

I would love to increase the sector size without formatting with specific tools, but I've read it's failure prone so I would prefer to skip that method.
Any help would be appreciated!

 

[kdragon75]

Your easiest bet is to do a file copy in windows. That said, I would repair the old zpool first.

What's the reason for file based extents? I prefer zvols as it gives me more control.