250GB over "100Mbps" ethernet/SMB (Windows Share) will never get 100Mbps, maybe more like 40Mbps, or even less. So that 2Tb will take 5000s, or about half an hour, at best, possibly much longer.
With correct network and host configuration you should be able to get at about 11 megabytes per second over 100mbit.
Your Windows machines get 88Mbps over 100Mbps ethernet?
no, but my linux machines with samba
i'm no windows guy but even nt4 was able to saturate a 100FD serving big files when configured properly.
best regards,
Hari