Dell MD3220 SAS Round Robin with VMWare

Hello all. I three Dell R710 VMWare hosts and a Dell MD3220 SAS SAN with dual controllers. The hosts each have a dual port SAS HBA and the ports are plugged into both array controllers. I'm having some disk performance issues and I'm trying to enable round robin to make use of both paths. When I change the path policy in VMWare from MRU to round robin, the paths still show one active, the other standby. Host has been rebooted. VMWare is version is 5.0.
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It works like you describe. One of multiple paths is used at any given time. It would be same on Windows, Linux or solaris or whatever OS you might install, be it Dell, HP, IBM, Fujitsu, or mix of 3 of them.

PS this is correct and final answer, dont tell me wrong unless you know better.
Andrew Hancock (VMware vExpert / EE MVE^2)VMware and Virtualization ConsultantCommented:
What path policy does Dell recommend, it can be "SAN" specific, and sometimes there can be additional policies which you need t import/install on ESXi.
Flexible_SystemsAuthor Commented:
I'd have to check with Dell. The warranty lapsed on the SAN so I have to wait until it's renewed so I can call them. gheist, i understand what you mean but when I look at a different client of mine running a fiber channel SAN and using round robin, I see the paths show acitve (IO) and active
active io
This particular client is set for round robin and I see this

active standby
It's my understanding that round robin would utilize both paths to increase throughput
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It works with iSCSI or NFS NAS (where load balancing is handled by network layer, not storage driver)
You can install dell vcenter plugin, which will choose right path selection policy without much effort.
Andrew Hancock (VMware vExpert / EE MVE^2)VMware and Virtualization ConsultantCommented:
Round Robin (RR): The VMW_PSP_RR policy uses an automatic path selection, rotating through all available paths, enabling the distribution of load across the configured paths.

For Active/Passive storage arrays, only the paths to the active controller will be used in the Round Robin policy.
For Active/Active storage arrays, all paths will be used in the Round Robin policy.

Flexible_SystemsAuthor Commented:
Andrew, yes that is what I'm looking to do. I have done it it past with other arrays. Dell's documentation on the MD3220:

MD3220 dual controller model – Dual, active/active controllers in a 2U, 24 drive 2.5” HDD enclosure
provides the combination of a highly available storage solution with a high spindle count to maximize IOPS
when using SSD or 15K, 2.5” SAS drives.

I'm not sure what I'm missing here. I'll have to wait until the warranty comes in so I can call support.
Andrew Hancock (VMware vExpert / EE MVE^2)VMware and Virtualization ConsultantCommented:
Use round robin, but Dell do have additional vibs, that can be installed, which add additional path selection policies, which are in additional to VMware's supplied routines.
Flexible_SystemsAuthor Commented:
So the warranty was purchased and applied. I called Dell and they said that the MD3220 direct attached SAS is not active/active so I cannot use round robin.

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Flexible_SystemsAuthor Commented:
Called Dell to resolve
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