Redundant HBAs

[eagleh]

Just a simple quick question. We have two ESX connected to SAN. Each ESX has two HBAs for redundancy purpose. I just want to know if network traffic going through these two HBAs are dynamically balanced or one of those is sitting idle like a backup? Any documents about this?

Thanks.

[mcowger · Accepted solution]

Unless you have enabled experimental round robin mode, one of the HBAs is sitting idle.

--Matt

[LarsLiljeroth]

Hi

As mcowger describes it one is working and one is idle. But if you have an Active/active SAN you can choose witch one is the preferred path

and by doing this you can spread the load one both HBA to multible LUNS. By default i think MRU is chosen. See more about it here. -> http://www.vmware.com/pdf/vi3_san_design_deploy.pdf


Best regards

Lars Liljeroth

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[BUGCHK]

It is not that simple whether the second adapter is used or not. It depends on the SAN topology, the failover configuration and whether you have an active/active or active/passive array.

For example, if you have two VMFS volumes and an active/passive array that allows to divide the ownership to both controllers, you can still create a configuration that makes use of both adapters in an ESX server.

Will it give you more performance? Oh, good you did not ask this question