VMWare, Blades, and Multiple VLANs

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Aug 19th, 2008
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Hi Everyone,

I'm using a blade center integrated switch that only offers one NIC to each blade, so I guess you can think of it the same way as a physical server with only one physical NIC - one VMNIC essentially.

The server guys want to have vnics for iSCSI, Data traffic, Vmotion, and backup for EACH blade. It makes sense to trunk from the external Cisco switch to the Integrated bladeswitch, from the bladeswitch to the vswitch, and then from the vswitch down to each particular blade, but the network configuration within vmware is still confusing.

From reading the design guide for VMWare at cisco.com/go/srnd, it sounds like I need "Virtual Guest Tagging," which doesn't seem to be a best practice for VM performance. Regardless of performance, is that correct?

If this is the case, I'm still confused on how to properly setup the vswitch, port group, and VMKernel and Service Console Ports.

Can anyone break this design down for me?



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Giuseppe Larosa Tue, 08/19/2008 - 12:15
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Hello Jason,

are you referring to this doc


see figure 39:

with only one NIC you need a trunk and the use of vlans, vlan tags are needed to distinguish frames of different vlans it shouldn't cause a performance penalty.

We have some ESX servers and we provide them two trunks with multiple vlans

(they are not blade may be)

But vmware config is made by servers' people.

I just wanted to say that in our case we don't config the vmware of course no limits on what can be done.

However, try to access docs on vmware web site on issues about vswitches, vnics etc.

Hope to help


jaye15394 Tue, 08/19/2008 - 12:23
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Right. At this point, I may be the one doing the "vswitch" and vmware networking configurations. So, I want to be sure giving one physical cable to the server, each VM can actually have acccess to multiple VLANs. From a general networking standpoint it's simple...so I'm looking to have help on the vswitch side of things...how many vswitches and how to do the service console, vmkernel configs..etc.

I'd love to see a screen shot of a networking config within the VMI Client of a similar config.

jaye15394 Tue, 08/19/2008 - 12:50
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Thanks for the response. I'm looking for something like my attached screen shot. Can you provide that?



jaye15394 Tue, 08/19/2008 - 13:22
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Thanks. It looks like you have multiple VLANs being used, but one VLAN per VM. What about multiple VLANs per VM?

don-sullivan Tue, 08/19/2008 - 13:45
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Multiple VLANs to a single VM are no different. Simply add another network card with a seperate VLAN. I'm attaching a couple of Screenshots to illustrate the use of multiple VLANs on single VM.

Willem de Groot Wed, 08/20/2008 - 01:27
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What hardware do you have?

is it IBM or HP or..?

What switch module is used in the bladecenter?

We also have a bladecenter (IBM) with Server-connectivity-modules. We had to config those as well!



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