I'm having trouble with MPIO on a new server I set up recently. It's an x3550M4 with Intel NICs. 4 are the builtin Intel I350's. And I have a dual port PCI Intel I340-T2. Windows Server 2012. I have this server connected to 2 different SANs, one is a Cisco NSS326, and the other is an IBM DS3300. The NSS326 has 2 NICs and works great, using round robin. Disk IO is good, and iSCSI saturates both NICs when I copy data to/from it. I'm having trouble with disk IO speed on the DS3300. If I set it to round robin with subset, and it only uses one NIC, speeds are pretty good (with crystal disk):
Sequential Read : 103.471 MB/s
Sequential Write : 69.447 MB/s
Random Read 512KB : 36.963 MB/s
Random Write 512KB : 44.258 MB/s
If I enable round robin so it uses 2, 3 or 4 NICs, speeds drop to abysmal levels, like 1/10th of the rr-subset speed. I started the disk test 30 minutes ago, it still hasn't finished.
My network gear is pretty good- I have 2 Cisco 3560G switches. They are connected to our core 3750 switch, but I don't think any traffic passes that way since the server NICs & SANs are on either one of 2 subnets, so iSCSI traffic stays within the switch. One other thing that may or may not be relevant- my NICs are using the builtin Microsoft drivers b/c I can't seem to find any Intel drivers for them on the IBM site as yet.
I'm at a loss as to what is the problem here. I've torn down and rebuilt my MPIO/iSCSI settings multiple times. I triple checked everything I can think of. Any advice greatly appreciated.