May 24, 2010 1:58 PM
Multipathing for Software iSCSI - Load Balancing
Hi,
I would like to fully understand iSCSI Load Balancing with Software iSCSI and I would like to make the best of an low-budget Software iSCSI system. Se my configuration below:
On my storage I have enabled multi path to single LUN.
On both ESX servers I have enabled Multipathing with Round Robin Selection Policy on the iSCSI Paths (have done everything exactly as it is shown in "iSCSI SAN Configuration Guide" for ESX 4.0 u1. And It works, I would just like to check if I got this correct: so the Load Balancing function for the software iSCSI configuration can not provide more than 1 Gb throughput for single ESX server, no matter how many connections are used for multipathing, is this corret? Because as I have seen the traffic goes like this:
A = path 1 (first cable to the switch and on to Storage)
B = path 2 (second cable to the switch and on to Storage)
x = traffic from ESX 01
traffic:
A B
x /
x /
x /
/ x
/ x
/ x
x /
x /
x /
/ x
...
So only one path is active at one time. This would mean that more then 1 Gb of throughput to the STORAGE can only be achieved when more than one ESX server is active at a time - for example 2 servers - and both are configured for Round Robin multipathing? But not guaranteed, it is a matter of order of requests, in ideal scenario when Round Robin algorithm would be so lucy to select the exact oposite paths on ESX 01 and ESX 02:
A = path 1 (first cable to the switch and on to Storage)
B = path 2 (second cable to the switch and on to Storage)
x = traffic from ESX 01
y = traffic from ESX 02
traffic:
A B
x y
x y
x y
y x
y x
y x
x y
x y
x y
y x
...
So please, am I thinkig right here?
Are there any other methods to get more than 1 Gb throughput on an low-budget Gb iSCSI Software system configuration? Has anyone successfuly configured LACP (Link Aggregation Control Protocol http://en.wikipedia.org/wiki/Link_Aggregation_Control_Protocol#Link_Aggregation_Control_Protocol) on vSphere 4, or it is not supported anyway?
Thanks for help!
--
Kind regards, Marko.
