Vmotion a host, but can't ping until the VM transmits...

[nashwj]

I ask a lot of questions on here....

Was at the same site as my other question about the trunk ports.  Their environment is three separate networks.  Internal is a 3750 switch stack.  DMZ1 is a single 3750, and DMZ2 is a single 3750.  None of these are connected to each other.  The 1Kv install is fine and working really well for all three network environments, except for one detail.  If I vMotion a VM that is connected to the Internal network from one host to another, I can't ping that VM until the VM itself sends out a frame.  On a busy server it's instant.  On a dev or test system it takes a while unless I make it do something which can be as simple as typing a bad password in the login box.  Now...VMs connected to the DMZ1 and DMZ2 networks (single 3750 each) don't do this.  They work as expected.

This problem wasn't there before we moved to the N1Kv from the standard vSwitch.  So the two changes are:  1.  Move to N1Kv  2.  Trunking and port-channels enabled.

The 3750 stack is running 12.2(50).  Any ideas here?  Once I flush the old MAC entry it seems fine from then on..but we have not re-enabled DRS yet since we aren't sure if a machine gets moved how long it might take to be responsive.

[ryan.lambert]

Morning... couple questions:

- Is the 3750 stack configured for layer3 at all?

- Do you have dynamic ARP inspection configured on the switches in the stack?

- Are your switch ports facing the 1KV configured as edge ports (spanning-tree portfast trunk) or normal STP ports?

From what I understand when a Vmotion occurs, there is a RARP, so if this is getting filtered out/not updated by the upstream switch you may have some issues with the 'automatic' updating of VM location across the stack. Not sure if this is the case, but something that comes to mind. Also, if you have fixed this by now, what was the resolution? Curious.

[nashwj]

Yes..the 3750 stack is configured for Layer 3.  It's actually their "core" switch stack.

Dynamic Arp Inspection is left at default:

3rd_Core#show ip arp inspection

Source Mac Validation      : Disabled
Destination Mac Validation : Disabled
IP Address Validation      : Disabled
No active or enabled vlans on switch.
3rd_Core#

They are set as Edge ports:

interface GigabitEthernet3/0/13
switchport trunk encapsulation dot1q
switchport trunk native vlan 3000
switchport mode trunk
channel-group 4 mode on
spanning-tree portfast trunk
spanning-tree bpdufilter enable

Still seeing the problem.

[mmehta]

Hi,

do you have trunking to the VM port. Can you please provide the configuration of

uplink port-profile and the VM port profile.

thanks,

Munish.