We have an EqualLogic 6000XV running in our production network. Two of the HBA/network ports are currently plugged in and active. While running some crude speed tests on the machines currently talking to the array, we see that traffic is doing some weird things. While copying large files from a Windows volume on the EqualLogic across the local network to another machine's internal drive, we see the two (MPIO) network adapters come up to about half speed, stay for a second, drop to almost nothing, then repeat. At absolute peak, speed seems to max out around 500Mbps. Everything is on 1Gb links.
So the iSCSI links appear to be doing these strange bursts, and then only to about half the max link speed. The iSCSI links go through a Dell PowerConnect 6220 with MTU turned up to 9216 and flow control on. The local network is running fine - when doing copies from internal disks to internal disks we see the LAN links max out all the way through.
I've checked out stats in the EqualLogic's Group Manager and there don't appear to be any errors on the network. The two unused links on the active controller are disabled.