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galibai
Contributor
Contributor

MS Cluster across hosts - Why 2 nics ?

In Cluster Across box Is it necessary to have 2 nics in each Virtual Machine?

One will be public and the other will be private?

I dont understand the reason behind this? In Physical world it was done so that we dont have to worry about the Cluster Heart Beat. But in Virtual World we should not be doing that because there wont be any Physical nics involved. Any ideas/suggestions?

Thanks

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krowczynski
Virtuoso
Virtuoso

You don't need two nics in an HA Cluster under ESX.

You create you Clustern through vcenter with drs, and that was it.

Of course DNS must be proper configured and shared storage!!

MCP, VCP3 , VCP4
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galibai
Contributor
Contributor

I am talking about MIcrosoft Cluster and not ESX Cluster Smiley Happy

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krowczynski
Virtuoso
Virtuoso

Sorry, yes if you create an MS 2003 Cluster you need 2 nics, one for your production network and one for heartbeat!

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galibai
Contributor
Contributor

but why ? if they are virtual nics they are not going to fail any ways right ?

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krowczynski
Virtuoso
Virtuoso

It is so, its ms config not vmware.

Buty why create an ms cluster und an HA ESX Cluster??

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galibai
Contributor
Contributor

lot of reasons

1) to apply patches so that vm are 24/7 up and running

2) political reason

3) Mgt. ease

4) Making VMware Admins life interesting Smiley Happy

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krowczynski
Virtuoso
Virtuoso

OK I see a lot of reasons!!:)

And what about the new feature FT in vsphere?

Would this not bes interestig for you?

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galibai
Contributor
Contributor

FT and MS cluster are 2 different technology.

First one will make sure your VM is up and running and the FT will not help u in MS Clsuter. It is more like a protection against host failure.

Hope this helps Smiley Happy

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atbnet
Expert
Expert

Yes 2 vNICs are required. One for the heatbeat between nodes. One for the all the actual network data.

Like mentioned you would use MSCS in a VMs for various reasons. You can acheive multiple benefits by using them all together as long as its done correctly.

You may also not have processors that support FT (Fault Tolerance VMs).

One thing for sure, use DRS and create a rule to keep the VMs on seperate hosts. That way if one ESX servers has a failure the VM node on another ESX server takes over.

Andy BSc (Hons)

VCP / vExpert / MCP / MCTS / TCSP

For Help, Guides and How Tos visit http://www.VMadmin.co.uk/

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Andy Barnes
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emcclend
Enthusiast
Enthusiast

We have 2 MSCS being used for file & print services. Just as you would in a physical world, 2 nics are still needed to seperate the network traffic from the MSCS heartbeat traffic. To get it setup was not too bad, however now after looking at it we are in the process of moving away from MSCS in a VMware environment. The reason for the change is because we have found out that by using a MSCS in a VMware environment, we loos some of the VMware functionality. One is the ability to migrate a VM from host to host. Since creating a MSCS across boxes requires you have to create a new SCSI, and that SCSI is tied to the box so no more hot migration, cold migration can still be done. Also we have and active/passive environment so what we have found is that the second VM is really just sitting idle doing nothing.

Now with a MSCS we are protected againist a hardware failure and a OS (MS) level failure to as the second machine is waiting to take over in the event of either failure. However with the complexity added to having a MSCS in a VMware environment we think that letting VMware take care of a host failure and moving the VM to another host is better and easier in the long run.

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thecomputermanu
Contributor
Contributor

Ok Nice and Dandy,

But required or not required, how do we add the private network nick and vm kernel, do we need to assign it a specific vlan?

I have been trying to implement this thing and I cannot figure it out how to add the second nic as a private nic.

Can anyone have an in detail doc. the VMWARE kb 1513 cannot be found!

Thanks

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