I have two CentOS 6 servers. I am trying to transfer files between them. Source server has 10GB/s NIC nd destination server has 1GB/s NIC.

Regardless to the command used nor the protocol, the transfer speed is ~1 Mega byte per second. The goal is at least couple dozens MB per second.

I have tried: rsync (also with various encryptions), scp, wget, aftp, nc.

Here's some testing results with iperf:

[root@serv ~]# iperf -c XXX.XXX.XXX.XXX -i 1
------------------------------------------------------------
Client connecting to XXX.XXX.XXX.XXX, TCP port 5001
TCP window size: 64.0 KByte (default)
------------------------------------------------------------
[  3] local XXX.XXX.XXX.XXX port 33180 connected with XXX.XXX.XXX.XXX port 5001
[ ID] Interval       Transfer     Bandwidth
[  3]  0.0- 1.0 sec  1.30 MBytes  10.9 Mbits/sec
[ ID] Interval       Transfer     Bandwidth
[  3]  1.0- 2.0 sec  1.28 MBytes  10.7 Mbits/sec
[ ID] Interval       Transfer     Bandwidth
[  3]  2.0- 3.0 sec  1.34 MBytes  11.3 Mbits/sec
[ ID] Interval       Transfer     Bandwidth
[  3]  3.0- 4.0 sec  1.53 MBytes  12.8 Mbits/sec
[ ID] Interval       Transfer     Bandwidth
[  3]  4.0- 5.0 sec  1.65 MBytes  13.8 Mbits/sec
[ ID] Interval       Transfer     Bandwidth
[  3]  5.0- 6.0 sec  1.79 MBytes  15.0 Mbits/sec
[ ID] Interval       Transfer     Bandwidth
[  3]  6.0- 7.0 sec  1.95 MBytes  16.3 Mbits/sec
[ ID] Interval       Transfer     Bandwidth
[  3]  7.0- 8.0 sec  1.98 MBytes  16.6 Mbits/sec
[ ID] Interval       Transfer     Bandwidth
[  3]  8.0- 9.0 sec  1.91 MBytes  16.0 Mbits/sec
[ ID] Interval       Transfer     Bandwidth
[  3]  9.0-10.0 sec  2.05 MBytes  17.2 Mbits/sec
[ ID] Interval       Transfer     Bandwidth
[  3]  0.0-10.0 sec  1.68 MBytes  14.0 Mbits/sec 

I guess HD is not the bottleneck here.