How many network interface card can you have on one computer?

[jimluu]

my motherboard comes with 2 gb connectors. When I use both, I get all sorts of errors. Now that I'm building a video/audio file server, I'd like to use some extra nic cards. I have 6 intel gb nic sitting around. Can I use all 6 if I had the space? How come it didn't work with 2 cards?

 

[jlazzaro]

6, lol...http://www.ezlan.net/faq.html#2nics

 

[QuixoticOne]

Sounds like you have a software driver / OS problem, or some really bizarre hardware problem. There should be no problem using both GB eth links at once.
What are you connecting them into? If it is a smart switch or something then maybe you have something misconfigured there?

Anyway the maximum NIC count is limited by your motherboard's slot capacity of course, and also the OS / driver related limits. Most decent OS / driver software should be able to take anywhere from 1 to 8 or basically unlimited numbers of NICs.

You'll run into a PC architecture bandwidth limit though when you start to go over 6-16 Gb/s ethernet NICs that are actually busy since then you'll have a possible 1GBY/second - 2GBy/s realm traffic rate and that is more than the south bridge / north bridge / memory / CPU bandwidth can spare depending on your chipset and how the driver works and what you're doing with the data etc.

Most PCs doing software based TCP/IP etc. struggle to keep up with even 2 Gb/s NICs in many cases, especially if disk I/O is needed to retrieve / store data.

 

[jimluu]

Thanks for the quick answers. I has an asus 939 mb connected to a router/switch. Must be something peculiar to this mb.

 

[JackMDS]

You can use as many cards as you slots for, however, when installed on a system with Client OS (None server Windows), you can Not use NICs that are configured on the same Network (Subnet).

 

[kevnich2]

You only need multiple NIC's if each NIC is connecting to different networks, as Jack stated. If all nic's are on the same network, of course you'll receive errors.

 

[Brovane]

From my server experience if you are going to use multiple NIC card the NIC driver software needs to be able to support multiple NIC's. Normally this is called building a Team for the network adapters. You will have one virtual NIC that has the network settings and then multiple phyiscal NIC's that are all part of the same time. One sever that I built had 3 Quad Port Intel network cards installed and I was using 10 NIC's at once with 4 different teams on different networks. You can configure your NIC teams to do load balancing or adaptive fault tolerance etc. Having two NIC's on the same network using different IP's is a recipe for weird issues. However you could have two NIC's on two different Networks that cannot route to each other.

 

[spidey07]

Broavane,

You gain nothing from doing what you described. There is no point to using that many NICs. Best practice is to use two NICs in a load balancing scenario to one switch, and other pair in a load balancing to a different switch and set the secondary pair up as a failover from the first.

there is also rarely a good reason to have a server on more than one network, the only good reason being an out of band management network. What I'm trying to say is just because you can doesn't make it a good idea.

 

[ihyagp]

You'd need NICs and an OS that supports teaming. s939 board w/ 2 nics sounds like nforce4 ultra - doesn't support teaming. You could drop several hundred on new network gear, but the bottleneck probably won't be the network interface in the first place - most systems won't saturate gigabit without fast drives and/or a raid array.

 

[yoda291]

Originally posted by: spidey07
Broavane,

You gain nothing from doing what you described. There is no point to using that many NICs. Best practice is to use two NICs in a load balancing scenario to one switch, and other pair in a load balancing to a different switch and set the secondary pair up as a failover from the first.

there is also rarely a good reason to have a server on more than one network, the only good reason being an out of band management network. What I'm trying to say is just because you can doesn't make it a good idea.

Now you're just talking the crazy talk.

10 nics, 4 teams -- that's only 2 nics on 4 networks each with 1 for OOB and 1 for sync to some other node or maybe even just using 2 nics for attaching to iscsi. Happens commonly for shops that want VM failover and virtual machines, but don't want to trunk or do vlans on a virtual switch. Totally acceptable practice especially in shops with dedicated and seperate sysops and netops staff.

There's lots of good reasons and best practices which require having 1 machine on multiple vlans.
Offhand I can think of
- bridgehead servers
- web application servers (presuming a database backend).
- most any high-end IPS system
- the aforementioned VMs.
- any number of networking devices that live as software or any proxy software really.
- most anything vpn-ish
- anything that uses carp or sync practically begs for multiple subnets.
- anytime you have dedicated iscsi equipment, you have to have a multi-homed machine somewhere.

Silly spidey.

 

[Brovane]

Originally posted by: spidey07
Broavane,

You gain nothing from doing what you described. There is no point to using that many NICs. Best practice is to use two NICs in a load balancing scenario to one switch, and other pair in a load balancing to a different switch and set the secondary pair up as a failover from the first.

there is also rarely a good reason to have a server on more than one network, the only good reason being an out of band management network. What I'm trying to say is just because you can doesn't make it a good idea.

The Server that was using 10 NIC's at once was a server that had Orion Network Performance Monitor on it. It was monitoring equipment on our main network and equipment on 3 different non-routed networks. The sever was setup with the NIC's of each team connected to each of our core 6500 switches. The last two NIC's were setup so I can when necessary RSPAN ports on our Access Layer Switches back to the core for data gathering. I am know using considerably less NIC's after I started trunking the NIC's. I now use 2 NIC's for all of the non-routed networks when I used to use 6. When I first deployed this server 2 years ago I didn't feel comfortable trunking NIC's.