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Nickwoo
Contributor
Contributor

Why vsan network change from vmk1 to vmk0 automatically?

Write on phone, may not detail enough.

vSan 6.02.

Every hosts have vmk0 and vmk1.

Vmk0 is managemnet/vmotion enable.

Vmk1 is vsan enable only.

Vmk0 and vmk1 are totally diff network, connect to diff switch, one for public, one for private, they cannot be communicated.

Then a day,  i enable vmk0 for vsan for all hosts when vmk0 is still with vsan enable.

Now vsan only use vmk0, not vmk1.

Question.

how can i switch vmk0 to vmk1 for vsan network without downtime?

How can i chek which network do vsan use?

I used disable/enable to estimate which network vsan use, is there a cmd to check?

How do vsan choose which network when more than one vmk set vsan enable ?

Thanks.

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TheBobkin
Champion
Champion

Hello Nick,

Click a host > Manage > Networking > Vmkernel Adapters

Move the slider or tab so that you can see 'Virtual SAN' Enabled or Disabled on the interface.

You can check which VmkNic is in use using:

#esxcli vsan network list

"how can i switch vmk0 to vmk1 for vsan network without downtime?"

You can do this using edit settings to disable vSAn Traffic on this vmk or you can do this from the command line using:

#esxcli vsan network remove -i vmk0

(double-check that vmk1 still has this enabled before doing this)

I tested this in my lab just now, as in your case - enabling vmk0 (vmk2 was vSAN enabled) switched it to vmk0 in use, this is likely a default to use lower vmk/IP.

Removing vmk0 using the above command caused no VMs to go down or any Objects/components to change state, it instantly switched back to using vmk2.

Feel free to test this in a HOL lab or something before doing it on your environment to verify for yourself that there will be no negative outcome but I doubt there will be, even if there was a short loss of connectivity vSAN nodes seem to be able to withstand very brief network loss pretty well.

Bob

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Nickwoo
Contributor
Contributor

hi,

I tested on lab.

VM A on host A, its datastore and copy are on host B and host C.

When i disable vsan on vmk0, host A cannot access datastore, and VM A crash.

Is there a way to change the vsan neowork on all of the hosts in one tine?

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TheBobkin
Champion
Champion

Hello Nick,

"When i disable vsan on vmk0, host A cannot access datastore, and VM A crash."

- Are you positive that all hosts in this cluster had multiple vmk interfaces with vSAN-traffic enabled on them and that these were all able to connect with the interfaces on the other hosts?

I tested this two more times in a HOL lab (unfortunately not real hardware this time) and one of the times when ENABLING the second vmk for vSAN on a host one VM (CentOS) crashed, on disabling the secondary vmk adapters no VMs crashed. So I tested the whole process again, this time when enabling nothing occurred, when disabling them nothing occurred, so I reckon the first crash was likely due to the HOL labs being slow (nested is not ideal!).

Did you test this in a lab backed by physical boxes?

"Is there a way to change the vsan neowork on all of the hosts in one tine?"

- Not really.

You could always vMotion all VMs off each host before switching the networking, or schedule *potential* downtime if you are concerned.

Bob

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admin
Immortal
Immortal

I would suggest you to put hosts into maintenance mode then change it.

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