I'm having an HA performance Issue involving MPIO on my Windows 2008 R2 Servers connecting to the back-end StarWind Storage. We have a 2 node HA Cluster running version 5.8.1964. The issue is that when we specify all 4 paths to our storage in MPIO, the performance is only about 20% of what we get otherwise. In other test scenarios we can fully saturate the Gigabit links (99%), but with HA and Round Robin to all 4 paths we top out at 20%
We have been doing testing using HA Targets created with RAM disks on the StarWind nodes to take the underlying disk i/o subsystem out of the equation. All testing has been done using IOMeter using some metrics mentioned in other posts (4 workers / 64 outstanding IOs / 32K 100% read, etc)
Here is our basic setup on each StarWind Node:
- Single 10 Gigabit crossover between the two nodes for Sync Channel
- 2 Gigabit Ethernet NICs on separate subnets for ISCSI traffic
Here is our basic setup on the Windows 2008 R2 servers connecting to the Starwind Nodes:
- 2 Gigabit Ethernet NICs dedicated for Storage Traffic
The issue seems to be related to using more than one path in MPIO per physical NIC. If I hard-code the Round Robin Policy to use only one Active Path per physical NIC then my HA performance jumps to fully saturating both Gigabit NIC connections to 99% utilization. And it does not seem to matter whether I specify all the traffic to go only to one of the two nodes or to both nodes. The issue does not seem to be either "HA-related" or "node-related", but instead just related to MPIO:
- MPIO Screen Shot.png (10.69 KiB) Viewed 13396 times
Any ideas?