NIC Teaming

[DonDavisFCB]

My NOC say that their switches (Cisco 3750s) only support 4 etherchannels per switch stack. How are you handling high availability, short of HACMP. I have more than 4 AIX servers per cabinet. Is there a way to team two NICs on an AIX server using one IP address and hardware address takeover, similar to HACMP? I need to do this on many AIX P4 mission critical servers that currently have only a single ethernet connection. I have additional NICs on these servers but cannot connect them with multiple IP addresses on the same network.

My question is: Can I configure the backup adapter without configuring etherchannel, keep a single IP address on two NICs and have hardware address takeover?

 

[khalidaaa]

hmmm,

I'm still new to the HACMP clustering thing but i can share with you our configuration in my company.

we have three clusters, each of these clusters have four ethernet cables. Two of these ethernets are standby (one for each node) And the other two for service IP addresses for each node.

So each node has two IP addresses. The reason for having the Standby connection is one for heartbeating and the other reason is for redundancy (when the service IP adapter failed, the adapter takeover will occur replacing the standby IP with the service IP).

So now back to your question, according to my setup, I don't think its possible not to configure a standby IP address on the backup (we call it secondary) node. There should be a way to get the heartbeating between the two nodes for both the nodes to know that the other is alive!

I don't know if it works the way you suggested doing the ethernet logically. If you are running AIX 5.3, there is a way for you to creat virtual ethernet adapters on the same NIC.

So with your setup, you can assign one ethernet port for each server and then create two virtual adapters on the same port making one adatper standby and the other service.

I'm not sure this will work but its a feature in AIX 5.3 and its worth trying

If i could be of any help, please feel free to ask

Regards,
Khalid

 

[DonDavisFCB]

Khalid,
Thank you for your response. Mabe I did not explain my problem clearly. I want to do etherchannel. BUT, my NOC says no. They would have to buy more switches and have a lot of unused ports. I need to configure two NICs on the same server. The second NIC would take over the IP and the MAC of the failing NIC.

Is there software or scripts that can do this?

Don

 

[mbourne2006]

Have you considered VIPA ?

http://inetsd01.boulder.ibm.com/pseries/pl_PL/aixbman/commadmn/tcp_vipa.htm

 

[DSMARWAY]

hi ,
If i understand you correctly , you still need to physically connect the 2nd NIC to the switch so when the 1st on fails then 2nd NIC has the service address on it
what would happen if the switch port fails ( single point of failure) you should at least cater for single point of failure


Which version of HACMP are you running ?
Because on 5.3 , theres no terminology as standby interface , basically you have one interface which will have service address on it , the rest can be setup as boot so if NIC 1 fails it will automatically fail over to NIC2 and so on.

hope this hasn't gone off at a tangent

i'll see if NIC teaming over single cable connected to single switch port is available ( what version of AIX and HA are you running ) I've also seen NIC 'teaming' for performance / load balancing traffic either at switch end or server end , but pysically 2 cables are present

 

[jstacey]

If you want to do failover only you create an etherchannel and select the primary ethernet adapter only, then as select your secondary ethernet adapter as teh backup adapter.

Configure the newley created etherchannel with your IP and test.
To test just start a ping and pull the primary ethernet cable.

We do this on all our servers AIX, Linux, Netware and Windows, plugged into diffrent switches/routers on diffrent breakers for increased reliability.

 

[amphibient]

you might need to work around the switch hardware details some other way....but to set up etherchannel, simply go via: smitty etherchannel. One other possibility would be to have your networking group mirror ports to the extra NIC. This way both NICs in the etherchannel trunk would have the same traffic coming to them -- whether this affects the cisco hardware's count for actual etherchannels, I don't know, but the end result is similar.