Multiple Nic cards for servers

I recently took over a site and the servers all have more than one nic card. I want to utilize the additional nics to help performance on the network. All the servers are HP & are connected to a Catalyst 3750 Gigabyte switch. I've got one server that's running SQL with 4 database instances. I've got a file server & 2 domain controllers (one of the DC's is a dhcp server as well & both DC are DNS servers). From what I've read it's not recommended to team nics for for a domain controller or dhcp server, but I've seen it done effectively. Can someone please give me incite on what's the best use of the additional nic cards on these servers. Thanks in advance
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HP has a utility to team NICs. But I have always heard you shouldn't just like you did.  We always disable one NIC
I'm using Intel load ballansing teaming on DC without problems. Install the last drivers for NIC.
Its best practice to team NICs in servers especially DC's/DNS'DHCP - the NIC will then not be a single point of failure.

Before you go and team, make sure the NIC's are supported in a teaming environment for the OS on the server.
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I think you are thinking not to multi-home a DC which is with different IP addresses, teaming them is not the same, they would share and IP address and balance/fail-over between the NIC cards as if they were a single entity.
You can consolidate them to increase the network performance.
In Windows it is called bridging, in Unices - lagg (Link aggregation)
In cisco this technology is calleg etherchannel.
I.e. if you have two 1000 Mb/s NICs then after aggregating them
you'll get almost 2000 Mb/s throughput.

On the DB server i think it's better to split NICs between different instances
Darius GhassemCommented:
There are issues with NIC teaming on Windows 2008 Servers when running on Doman Controllers and DNS servers. I have worked on many problems  that ended up being the network team causing the issue the whole time on DC and DNS servers. The problem is that network teaming is done by a third party software which a lot of the times is the actual problem.

You can create network team if you would like to test but I would make sure you have updated drivers, firmware, and network card software fully updated.

Now with SQL servers I recommend using more then one NIC as a network team this can give you some more bandwith as well redunancy.

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PowerEdgeTechIT ConsultantCommented:
As darius eluded to ... use the NIC manufacturer's software for teaming.  If HP has a utility to team them, it may just be an HP-packaged driver from the NIC's manufacturer, but if it isn't - if it is an actual "third-party" utility - then don't use it.
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