topic Re: HBA load balancing in MSA Storage

HBA load balancing

MaryJ — Wed, 17 Feb 2010 18:37:32 GMT

We're using HP Proliant DL 300/500 servers, with HP branded Qlogic HBA cards, that are connected to HP EVAs. We have noticed that most of the luns presented to our hosts, go to Controller A as the preferred path. We'd like to balance this load between controllers. Does HP provide a tool for load balancing? Or would the SANSurfer tool provided by Qlogic work?

Thanks in advance.

Re: HBA load balancing

Uwe Zessin — Wed, 17 Feb 2010 20:18:51 GMT

What EVA and operating system are involved?

On a modern setup with Windows you can make a manual load balancing by setting the 'prefered paths' of the virtual disks on the EVA and then tell the MPIO DSM to enable Adaptive Load Balancing (ALB).

On VMware ESX4, assign your vdisks and then enable RoundRobin.

Re: HBA load balancing

Matt Weil — Thu, 18 Feb 2010 01:42:53 GMT

ql2xlbType=3 should be set on the qlogic driver.

This should keep your luns bouncing from one controller to the other automagicly.

attached is some scripts to help balance luns

use at own risk......

if you access luns between the controllers you are at risk of saturating the link between the controllers (poor performance).

if controller A has a lun and a host is accessing it through controller B...

controller B will access the lun through the connection between the two controllers.

ideally the controller owning the lun is the controller your hosts should be accessing it through.

Re: HBA load balancing

MaryJ — Thu, 18 Feb 2010 19:12:27 GMT

This is a RHEL 4 environment. I checked the settings for ql2xlbType and we have it set to the default (0). We'll try changing it to 3. Thanks!!

Re: HBA load balancing

Matt Weil — Fri, 19 Feb 2010 02:20:49 GMT

2 or 3 should be fine for EVAs