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So confused about vSphere round-robin iSCSI Multipathing...

baselinept
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Hi all,

Hope any of the gurus on this community can help clarify something for me...

Essentially I would like to know if it's possible to do vSphere iSCSI NMP with only 2 NIC's per FAS node and without stack capable switches (i.e no cross-switch etherchannel)?

Hypothetical Example:

In this case the core switches don't support any kind of stacking at all, and therein lies the problem.

I know that because of this and if I want a minimum of safety (redundancy) I have to connect each of the 2 NIC's on the FAS node to the 2 Switches.

Example:

Now, I know that in this configuration I only have failover capacity between each NIC on the FAS nodes. But that’s just it, I would like to know if it’s possible using this setup to have multipathing iSCSI using round-robin NMP on vSphere.

Let’s say I configure 2 vmKernel NICS on one ESX vSwitch using IP’s from our example Lan (IP 10.10.0.6 and 10.10.0.7). Bearing in mind that the 2 NICs on the vSphere will be connected in a manner similar to the FAS nodes, one cable to each of the 2 switches.

Now, if I specify round-robin on the 2 vmKernel NIC’s and then use the VIF’s as iSCSI targets, will I get multi-pathing to each node? That is, will the vSphere NMP automatically balance the paths?

Or, do I have to create 1 VIF alias on each node (as suggested by the “vSphere SAN Configuration Guide”) and then use those 4 VIF’s as iSCSI targets?

Confused? You bet 

Thanks in advance

Kind Regards,

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