On Apr 1, 2010, at 3:30 AM, Holland, William L wrote:

toaster-0 and toaster-1 are 2 different host names that will resolve to 2 different IP addresses.  They can be in the same subnet or different subnets.  If your VIFs are on the same filer and subnet and you wish to have your clients talk to them specifically, they have to resolve to 2 different names.  This can be done by host files on your client or by DNS entries.


While this is true for NFS, I've seen where lockd and some other UDP based protocols would respond from another interface on the same subnet (quotad and SNMP is a good example) .  I can currently reproduce with SNMP.  

Example

192.168.1.1 - VIF 1 IP

192.168.1.2 VIF 2 IP

mount command against VIF 1 will see a response from VIF2 IP for some of  protocols like mount, snmp,   The actual *NFS* traffic (port 2049) will always come from VIF1.  I don't necessarily see an issue with this, as the RPC mechanisms are higher level than the IP stack, but some OS's might not like this asymmetry. 

I can currently reproduce this with SNMP on 7.3.1.1P8.

I pull VIF 1, but the return traffic was coming from VIF2.   the host based firewall did not like this,  so I just configured the polling box to use VIF2 and it was happy.   I would speculate that it'll happen even if the two interfaces aren't vifs, but I haven't tested.

~Max







 
From: owner-toasters@mathworks.com [mailto:owner-toasters@mathworks.com] On Behalf Of Romeo Theriault
Sent: Thursday, April 01, 2010 5:47 AM
To: Funke, Stefan
Cc: toasters@mathworks.com
Subject: Re: routing issue with 2 vifs on same subnet?
 
Hi, Thanks for the response.  

On Thu, Apr 1, 2010 at 6:21 PM, Funke, Stefan <Stefan.Funke@netapp.com> wrote:

You may be correct, but I didn't think this was the case, especially since I read this in the 7.3.2 Network Management Guide:

Balance NFS traffic on network interfaces
You can attach multiple interfaces on your storage system to the same physical network to balance network traffic among different interfaces.
For example, if two Ethernet interfaces on a storage system named toaster are attached to the same network where four NFS clients reside, specify in the /etc/fstab file on client1 and client2 that these clients mount from toaster-0:/home. Specify in the /etc/fstab file on client3 and client4 that these clients mount from toaster-1:/home. This scheme can balance the traffic among interfaces if all clients generate about the same amount of traffic.
Your storage system always responds to an NFS request by sending a reply using the interface over which the request was received.
 

Thoughts?

Romeo