esxi 4.1 network issue, when vmk0 is unreachable, vmk1 is also unreachable? bug?

[andreas190386]

hi @ all,

maybe someone could help me, I have configured an esxi host with

2 network cards, each network card goes to a seperate switch, when I unplug the cable on vmnic0,

vmk0 is unreachable, thats ok. But why is vmk1 also unreachable?

I have atached a picture of my network configuration.

[J1mbo]

I would suggest instead a single VMK on this subnet, and bind the second NIC to the first vSwitch, as a standby if you don't want to use active-active.

[andreas190386]

hi,

thanks for your post, but in my configraution i need this configuration, there are some iSCSI SAN´s

in the Background, with different subnet´s,.......but I think this informatin is not relevant.

I don´t understand why vmk1 gets unreachable,.... in my oppinion it should work, when this is not possible, to configure it like in my picture,

I can not implement the esxi, because when one switch is death, my esxi management network is not reachable anymore, expect vmk1 is unreachable,

then in this case I can reach vmk0,.....

I have also tried to configure it with explicit failover, same behavior, when the vmk0 get´s unreachable, vmk1 is also death,...

hope someone can help me, I didn´t find something in the internet, which describes my problem,....

maybe it is neccessary to configure an advanced option in the esxi, but I do not know which,...

best regards

andreas

[J1mbo]

But these too vmks are on the same subnet?  Is your client on the same subnet?

[Walfordr]

Run these command on your host and you'll find out why:

esxcfg-route -l

esxcli network neighbor list

ESXi adds the first VMK as the routing interface when other VMK is on the same network. If both NICs are on the same vSwitch in Active/Active or Active/Standby the failover policy will kick in and utilize the second NIC, the connection still goes through VMK0.

Split VMK1 to another subnet and you'll see the difference with the commands above.

It kind of push people to use best practices (seperate management network from VM, iSCSI, etc), but some people cannot afford to.

See example:

--BEFORE SEPERATING NETWORK--

~ # esxcfg-vswitch -l
Switch Name      Num Ports   Used Ports  Configured Ports  MTU     Uplinks
vSwitch0         128         4           128               1500    vmnic0,vmnic2

  PortGroup Name        VLAN ID  Used Ports  Uplinks
  VM Network            0        0           vmnic0,vmnic2
  Management Network    0        1           vmnic0,vmnic2

Switch Name      Num Ports   Used Ports  Configured Ports  MTU     Uplinks
vSwitch1         128         3           128               1500    vmnic1

  PortGroup Name        VLAN ID  Used Ports  Uplinks
  VMkernel              0        1           vmnic1

~ # esxcfg-route -l
VMkernel Routes:
Network          Netmask          Gateway          Interface
10.9.8.0         255.255.255.0    Local Subnet     vmk0
default          0.0.0.0          10.9.8.1         vmk0

--AFTER SEPERATING NETWORK--

~ # esxcfg-vswitch -l
Switch Name      Num Ports   Used Ports  Configured Ports  MTU     Uplinks
vSwitch0         128         4           128               1500    vmnic0,vmnic2

  PortGroup Name        VLAN ID  Used Ports  Uplinks
  VM Network            0        0           vmnic0,vmnic2
  Management Network    0        1           vmnic0,vmnic2

Switch Name      Num Ports   Used Ports  Configured Ports  MTU     Uplinks
vSwitch1         128         3           128               1500    vmnic1

  PortGroup Name        VLAN ID  Used Ports  Uplinks
  VMkernel              0        1           vmnic1

~ # esxcfg-route -l
VMkernel Routes:
Network          Netmask          Gateway          Interface
10.9.7.0         255.255.255.0    Local Subnet     vmk1
10.9.8.0         255.255.255.0    Local Subnet     vmk0
default          0.0.0.0          10.9.8.1         vmk0
~ #

Hope that explain it.

Message was edited by: Walfordr corrected typo on neighbor command

Message was edited by: Walfordr corrected more typo