VSAN

[kaschauh]

Hi,

I am a little confused about how a servers would decide on which VSAN to route through when there are two VSAN confiured.

Considering the following topology where we have VSAN 10 and VSAN 20. 

MDS1 is configured for VSAN 10. 

MDS2 is configured for VSAN 20.

How would server decide whether to send data on 10 or 20?

                Storage

               /         \           

           /               \

       /  (10)     (20) \

   MDS1             MDS2

     |                             |

     |_(10)_|SRV|_(20)_|

Thanks

Kashif

[Walter Dey]

The Server doesn't have any Information about vsan's (doesn't do vsan tagging). In your case, FC multipathing Software on your host will most likely see the same lun over 2 different path, one over vsan 10 resp 20. It does the decision on which Output port to send the traffic. Hope that clarifies your question.

Walter.

[kaschauh]

Thanks wdey.  So, how would FC multipathing software decide which output port to select (vsan 10 or vsan 20)?  Is that something that administrator decide as primary as secondary on the software?

Thanks

[Walter Dey]

As I said, multipathing is not VSAN Aware, it only sees paths. The Setting of multipathing can be set active/active, or active/standby; FC is very critical about out of order Frame delivery, therefore all Frames of scsci read or write would go out the same physical link (active/active topology).