Internal networking setup causing issues when vmotioning servers

[Julian_Milano]

I have 2 virtual servers setup where the client server "ClientA" connects to a SQL database on the database server "ServerSQL". I've found that on our VMware ESXi 6.0 farm that when I manually storage vmotion a large virtual server (2 to 6TB disks), the client server "ClientA" loses its network connection to the database server "ServerSQL" and shows a network error.

I believe that the storage vmotion traffic is being transferred over the LAN, and it seems to be somehow interfering with the normal server data network. How do I prove this and then fix it?

My Setup:

* 4x UCS B200 M4 servers setup as VMware hosts connecting via a virtual center server.

* Each host has 5 NICs:

---- vnic0 & vnic1 for VMOTION VLAN010 (IP: 192.168.1.1) and Management VLAN120 (IP: 10.96.12.51).

---- vnic2 is for all data VLANs for server network comms. VLAN010 (IP: 10.100.125.xxx)

---- vnic5 is for SQL Heartbeat network VLAN217.

---- vnic3 is for DMZ network VLAN101

Note that VLAN010 is defined as the VMOTION VLAN and a DATA VLAN on different NICs and I assume this is where the issue is?

[bayupw]

Hi Julian,

Did you vMotion (move VM from one ESXi host to another ESXi host) or Storage vMotion (move VM from one datastore to another datastore).

I don't think the vMotion/svMotion is impacting the VM connectivity, but if you have STP from your physical switch to ESXi, there could be connectivity loss for up to 50 seconds in my esperiences.

Make sure you have spanning tree portfast/edge on your physical switches to ESXi host conenction.

See this KB: STP may cause temporary loss of network connectivity when a failover or failback event occurs (10038...

Other than STP, I couldn't think any other reason why vMotion/svMotion would impact your VM connectivity.

But if you want to make sure, you can configure vSphere Network I/O Control to reserve VM data network connectivity