2 Network Cards for Bandwidth 1

[Grenage]

Hopefully we will shortly be gaining an old Compaq server to act as a fileserver, since our current one is too small and slow. Now since it will be connected to the switch by a 100m/b CAT5 connection like the rest of the workstations its bandwidth wont exactly be exceptional.

I was told by a friend that Compaq Servers can have a second Network card installed, and that the 2 can act as 1 to double the bandwidth with 2 cables going to the switch.

Does anyone if this is true, or where I might find some good information on how do configure this etc? I am assuming the second Network card would have to be of the same type, almost certainly a pair of compaq ones.

Sorry if the above isn't very informative, I haven't worked on any Compaq servers before, and never attempted to use 2 cards as 1.

 

[TheLad]

It's called Adapter Teaming. What kind of network cards are they (make etc..)? -----------------------------------------------------
"It's true, its damn true!"
-----------------------------------------------------

 

[Jiff]

Yes, there is. There is an option called Teaming, but I don't know whether it would work with Non compaq cards.

 

[Grenage]

Thanks

I'll take a look at the card type as soon as I can, its an old Proliant 6500 but it should do the job nicely.

 

[ntinlin]

Hi Grenage,

I had a problem trying to team using the older Compaq Thunderlan cards. Had better results with the newer Intel NC31xx cards, still Compaq branded though. Driver for cards supports teaming by default.

I actually took the NIC's out of some DeskPro EN's
The server specific cards are very expensive but they do theoretically reduce the load on your CPU.

Quite impressive when it works, especially with failover.

Neill

 

[Grenage]

Thanks

I've been reading up on it like a madman so I don't get caught out when the time comes. Microsoft had a nice guide but I think they probably over simplified it. I guess I'll just have to get the cards together and find out


Best to do this on a Saturday I think.

 

[oblio3]

There are three forms of NIC teaming:

1) TLB - Transmit load balancing. One NIC handles incoming requests, and two send outgoing. Good for media or download servers as the performance is asymmetric in the outgoing direction.

2) Failover (I forget their official name). Just like it sounds, one does all the work and the other steps in and takes over just in case of failure or performance degradation.

3) SLB - Switch Load balancing (think Cisco Etherchannel). After configuring the switch appropriately, both NICs are treated as one virtual unit with a common IP. This requires support and configuration on the switch end of things.

Hope this helps!

Sam

 

[Grenage]

Great thanks

I believe option 3 if what we will be looking for, although I did not know the cards worked as one, and required switch suppport. We are getting a new switch for the network along with the new server so I shall check it has the support.

Thanks for the heads up

 

[LittleScooby]

I have been doing some TLB tests with Compaq NC3120's lately. I have created successful adapter teams with them but I have run into issues I can't explain and I was hoping someone would be able to help.

The switch I am using is a Linksys 8+1 workgroup gigaswitch. It has 1 gigabit port and 8 10/100 ports.

I have 1 workstation that has an SMC 1 Gig NIC in it. When I simutaneously transmit to 4 servers that are on this switch, I get the appropriate transmitting and receiving speed from the gigabit adapter and the same appropriate speed when I transmit from one of the NC3120 teamed servers to multiple nics.

The problem arises when I transmit from one of the servers that has an NC3120 team of 2 or more adapters to the gigabit workstation.

For instance, if I use Netcps to send a huge memory dump (anywhere from 1 to 10 gigs or more) to the workstation with the gigabit adapter, the adapter team (on the transmitting teamed TLB server) barely enhances the bandwidth over just one nic. However, if that same NC3120 team is transmitting to multiple servers or workstations (meaning transmitting to more than one nic), I get the full bandwidth that I should expect with 2 or 3 teamed 3120's.

Anyone know why I get such lowsy rates when transmitting from the NC3120 team to a single gigabit adapter which should easily be able to handle 200-300mbps from an adapter team?

Just seems kinda strange.

 

[anawrocki]

I did simular testing and was initialy disapointed after doing some in-depth research. (I thought my four nic team was going to be 400 Mps)

My current understanding of all three flavors of Teaming is that there is neve a benefit when you are going from 1 node to one node. In other words, Cleint A requests data from server with 4 Teamed NICs, it gets the full bandwidth of 1 NIC. Client B requests data from server and the Team uses an idle NIC to service Client B, so-on and so-forth.

This is great if you have many clients to one server and it also gives you failover.

If you are going 1 to 1 you will have the same bandwidth (it may even be slightly slower due to overhead) as the if there were only one NIC per node but it pays off in high traffic scenarios.

 

[Grenage]

We recently implemented the adapter teaming and have been very happy with the results. Definately makes a big difference in server bandwidth for us

 

[rocketsensor]

Server Load Balancing can provide additional bandwidth in some situations and no extra bandwidth in others.

SLB uses a simple function of the destination mac address to determine which of the available ethernets to use. If the server is talking to lots of nics, the load is spread across the servers NIC's. If the server is talking to only one mac address, for example during a file transfere, the same server nic is always used and the max throughput is equal to one nic.

As most big servers are not on the same IP subnet as the users, the server will be talking mainly to the mac address of the router, again max throughput = one nic.

The switch also uses the same method to determine which interface to send each packet down. If the switch is using the destination mac address (deafult) to decide which interface to use to get to the server, it will always use the same interface, again max througput = one nic. It is possible to configure most switches to use the source mac address but this doesn't help much if the source mac address is the gateway router.

SLB can add bandwidth in certain situations, but in most situations it just adds complexity. For bandwitdth get gigabit. For redundacy get two nic and use simple fault tolerance.

When going gigabit do not forget to take into account the bandwith of your shared PCI bus!

 

[rocketsensor]

And what out for the driver version of the NC series nic.

http://www.cisco.com/warp/public/788/AVVID/nic_align_error.html

Get the network people to hard-set the switch port speed and duplex.