The following shuld be changed to enhance iSCSI traffic.

Solaris iSCSI tuning

Tune iSCSI perimeters

iscsiadm modify target-param -p maxrecvdataseglen=65536 
iscsiadm modify target-param -p datapduinorder=no 
iscsiadm modify target-param -p initialr2t=no 
# until CR 6858989 is resolved, do not set datapduinorder=no as previously recommended.
 
# a revised workaround is:
 
iscsiadm modify target-param -p maxrecvdataseglen=65536 
iscsiadm modify target-param -p initialr2t=no 
 
# until CR 6858991 is resolved, do not set maxrecvdataseglen greater than 65536.

For more information click here

Tune iSCSI sessions

Defult is 1 Sessions

initiator# iscsiadm list target-param -v iqn.1992-08.com.abcstorage:sn.84186266
Target: iqn.1992-08.com.abcstorage:sn.84186266
Alias: -
.
.
.
Configured Sessions: 1

To change to 4 Sessions

iscsiadm modify initiator-node -c 4

Disable TCP Fusion

echo 'do_tcp_fusion/W0' | mdb -wk

For more information click here

Disable Nagle’s algorithm

Append tcp-nodelay=1 to iscsi.conf

echo 'tcp-nodelay=1;' >> /kernel/drv/iscsi.conf

For more information on Nagle's algorithm click [http://en.wikipedia.org/wiki/Nagle%27s_algorithm here]
== Genral system tunining ==

ndd -get /dev/tcp tcp_xmit_hiwat 2097152 
ndd -get /dev/tcp tcp_recv_hiwat 2097152
ndd -set /dev/tcp tcp_max_buf 2097152
ndd -set /dev/tcp tcp_cwnd_max 2097152
# 10G cards
ndd -set /dev/tcp tcp_recv_hiwat 400000
ndd -set /dev/tcp tcp_xmit_hiwat 400000

Sun recommended Solaris iSCSI

Note: Make sure to disable sendtargets discovery
iscsiadm modify discovery -t disable
enable static

• iscsiadm modify discovery -s enable
• iscsiadm add static-config iqn.1986-03.com.sun:02:176382b3-e0ab-e94c-b86c-a052a46a6b21,10.20.16.240
• iscsiadm modify target-param -c 4 iqn.1986-03.com.sun:02:176382b3-e0ab-e94c-b86c-a052a46a6b21
• You have to re-login
• iscsiadm modify discovery -s disable
• iscsiadm modify discovery -s enable