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So we are using a pretty powerful server at work, a Dell PowerEdge R710 Server, which comes with 6 1GB NICs. I've searched and thought a lot but am hard pressed as to why one would want a server with 6 NICs, what would you use them for. There is an excellent related question Is there any reason to have 2 NICs on a server? However most of the answers make sense when you have 2-3 NICs but wouldn't need more then that. Here are some scenarios that would not need more then 2-3 NICs in my opinion:

  1. Redudancy (2 is enough)
  2. Separate physical networks (2-3)
  3. Backups on separate network (2)
  4. Bonded NICs to increase throughput - Just get one 10GB NIC and it's faster and simpler then 6 bonded 1GB NICs.

One Answer

In writing the question out I just thought of one answer, If you had 6 virtual guests running on the server you could let each one have it's own dedicated NIC. But I still would like to get more answers to this question.

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closed as not constructive by Greg Askew, RobM, pauska, Chopper3, EEAA Nov 29 '12 at 13:25

As it currently stands, this question is not a good fit for our Q&A format. We expect answers to be supported by facts, references, or expertise, but this question will likely solicit debate, arguments, polling, or extended discussion. If you feel that this question can be improved and possibly reopened, visit the help center for guidance.If this question can be reworded to fit the rules in the help center, please edit the question.

up vote 6 down vote accepted

This is going to get closed, but it's a design decision like anything. For example, a 10Gb NIC is only useful if you have a 10Gb port to plug it into. 10 1Gb NICs may plug nicely into your core switch. Additionally, you'd need two (on separate switches) for redundancy.

Taking your virtualisation route, it's very useful to have multiple NICs because it allows for more flexibility in carving up your network. VLANs are great, but ultimately you're forcing everything down one pipe and it's easier said than done to manage that traffic. And from a VMware specific standpoint, it's far far easier to manage your virtual networks with multiple separate NICs.

For example, you could have 2x for iSCSI storage, 2x for virtual machine production VLANs, 2x for backups (So as not to impact on the network if you want to run daytime backups, or the service is 24 / 7) and 2x for hyper visor management. That's 8, independent NICs right there that I can absolutely hammer without affecting the other services.

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You mentioned that this question will probably get closed. The question also has a -1 score currently. The related question Is there any reason to have 2 NICs on a server? never got closed and has a score of 8. Can you give any advice on how to improve the way I posed the question, just for future reference. Thanks for the great answer. – Marwan Alsabbagh Nov 29 '12 at 12:10
@MarwanAlsabbagh It's just age - the other question is from 2010 and the scope of this site has changed a lot. That question would definitely be closed if it were posted tomorrow. To be honest, your question is entirely fair & reasonable, it's just a bit too open ended. Take a read of our FAQ or pop into chat. – Dan Nov 29 '12 at 12:13

Virtualization. 6 is the least I'd want on a ESXi host, especially if you're using iSCSI.

2 for storage
2 for management/vMotion
2 for data

Or if you don't use iSCSI, you can separate management and vMotion traffic.

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You can still separate management from vmotion by using a shared switch with failover overrides, so that they won't jump nic's until there is an actual failure. Works nice :) – pauska Nov 29 '12 at 11:56
Neat trick. Do you have a doc on configuring it? – MDMarra Nov 29 '12 at 13:17
nope, but you can join chat and i'll show you – pauska Nov 29 '12 at 14:35

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