Ok, so we have three identical server-grade machines, that I'm labelling as follows:
1-OpenSolaris 2-Linux 3-Initiator(Linux) So your results are: '3-Initiator(Linux)' to '1-OpenSolaris': 630Mbits/s '3-Initiator(Linux)' to '2-Linux' : 520Mbits/s '2-Linux' to '3-Initiator(Linux)' : 733Mbits/s '1-OpenSolaris' to '3-Initiator(Linux)': 297Mbits/s So you can transmit data to a OpenSolaris server at a higher speed than you can transmit to a Linux server, which is good! However, when OpenSolaris is transmitting data it is slower, and is less than half the speed that Linux can achieve. As iscsi operates as a layer over TCP, to get good iscsi performance, we first need good TCP performance. I know previously that some people have recommended checking the settings for Nagle's algorithm. http://en.wikipedia.org/wiki/Nagle%27s_algorithm http://tools.ietf.org/rfc/rfc896.txt (Also sometimes called 'Nagel's algorithm to cause confusion!) Some people find it gives an improvements, others say no. It would be interesting to know how this affects your performance results, both iscsi and iperf. On OpenSolaris, I believe you disable nagle as follows: # ndd -get /dev/tcp tcp_naglim_def 4095 # ndd -set /dev/tcp tcp_naglim_def 1 # ndd -get /dev/tcp tcp_naglim_def 1 I'm not sure how you control nagle on Linux, so ask Google. If that does not work, maybe some of the other tcp tunable values will affect things: # ndd /dev/tcp \? Best Regards Nigel Smith -- This message posted from opensolaris.org _______________________________________________ storage-discuss mailing list storage-discuss@opensolaris.org http://mail.opensolaris.org/mailman/listinfo/storage-discuss
