Why is my MPIO connection to the SAN capped at 1 Gbps when using Linux?

Solution 1:

It turns out that the issue was related to the switch. When we finally replaced the HP with a new Dell switch we were able to get multi-gigabit speeds as soon as everything was plugged in.

Solution 2:

Just food for thought... we had Server 2003 boxes with software multipath IO on an HP ProCurve switch to Dell PS5000 SANs working fine... I will say that we had to fight with a lot of settings on both the Dell EqualLogic side and the software iSCSI side in Windows to get everything working smoothly however.

On Windows a crucial step in getting things working was switching the load balancing from "least queue" to "round robin" (this is from memory so cut me some slack if I'm not remembering the terms exactly right). Once we did that, we could see bandwidth to the EqualLogic banalcning across our three dedicated iSCSI NICs.

Make sure your iSCSI working scenario survives across reboots too! We had to tweak the order in which services start on Windows (by changing service dependencies) to get iSCSI and MPIO working "just right" after a reboot