Virtual Servers - Network confusion / Problems

[burgemaster]

Hi,

 

Im hoping someone can help me here who has a virtual network setup...

 

We currently have 3 x virtual server hosts. Each host has 4 virtual servers running on it.

 

I am a little confused on the networking and we are currently having a problem with network connectivity on a couple of servers.

 

When pinging the virtual server we get replys upto 14ms every now and again. This seems to be playing havoc with our thin clients.

 

Each host has several network connections, each of these are connected 1gig back to our main switch.

 

Am i right thinking that the correct setup is that on each host, one is used to connect the virtual servers to the network and the other is used for communication between the hosts?

 

Should these "communication connections" be going back to the main switch or should they be connected to a seperate switch that isnt connected to the network?

 

I am managing the virtual servers with Virtual Machine Manager and when looking at the Network overview it looks seriously wrong!! lol

 

http://www.uploadgeek.com/image-D99B_4C231987.jpg

 

All servers have connectivity but pinging some of them i get weird results?

http://www.uploadgeek.com/image-F2B0_4C231A06.jpg

 

Any help would be appreciated !!

[jamesfed]

Which hypervisor are you using? (Hyper-V/XenServer/VmWare/other)

Could we get a few more specs on the host servers to?

[burgemaster]

Thanks James,

 

Server 2008 R2 running Hyper-V. (2 Core installs and 1 full enterprise)

16GB RAM on each host

Each virtual server was created from a "Psychical 2 Virtual" conversion

Managed with Microsoft Virtual Server Manager.

Edited June 24, 2010 by burgemaster

[jamesfed]

Got an interesting problem there your host servers look like their setup fine (one network port for management (not connected to the VMs) and then virtual networks/adapters to the servers) so can’t imagine there’s any problems there.

 

All the same some good things to check might be-

Isolate your hosts network adapters (maybe dedicate one to a testing OS) and run pings to see if there’s any problem with the hosts adapter.

Check your physical network cabling/switches

Maybe run tracert to see which hop the increased latency is being caused at (could ID a problem with the network adapters/switches)

[tmcd35]

I guessed it was going to be Hyper-V, had similar problems myself.

 

Things to check -

 

In the nic properties for the card being used by the virtual machines:

- Client for Microsoft Networks is 'unticked'

- In IPv4 Properties:

..... - Assign IP automatically

..... - Advanced:

.......... - DNS: 'Register this connection's address in DNS' is 'unticked'

 

You could also set a higher Metric for this adaptor than the Metric on the other 'management' interface. This forces Windows to communicate on the correct nic by default.

 

On your DNS server check that only the (pressumably) static IP for the 'management' interface is listed. If there is more than 1 IP listed in DNS then delete the other un-needed entries.

 

Finally if you have multiple cards, how meny? What are they used for. Are any bonded/trunked. You should only have three connections/IP's (each can be a trunk, or not).

1 - static windows management interface

1 - connection to the virtual machines virtual switch

1 - for iSCSI/SAN if used.

 

Anything else and Windows is very likey getting confused over which NIC it is supposed to be communicating over.

 

 

Also, Only 1 nic (or trunk) should be connected to each 'virtual switch' in Hyper-V. You're not connecting the managemnt interface to the virtual switch as well are you?

[benIT]

I had this on one of my print servers that I converted using P2V (was physical Server) read something on MS that if the NICS were teamed at point of virtual convert or some drivers can mess things up. They recommended removing all drivers and old network utilities.

 

This may or may not help you out