It should work fine, but as long as you have two active links within the same subnet, it’s totally random which path will be used, since the destination is visible over multiple links.

 

If your client is expecting packets from server IP 10.0.0.1 and receives it from IP 10.0.0.2, it may drop packets, resulting in hanging mount requests.

If possible, please use different ip subnets or switch to a failover (single vif) configuration.

 

-Stefan

 

From: Romeo Theriault [mailto:romeotheriault@gmail.com]
Sent: Donnerstag, 1. April 2010 09:59
To: toasters@mathworks.com
Subject: routing issue with 2 vifs on same subnet?

 

We recently upgraded our SAN ethernet switches and moved from a config where we had one vif with all the nic ports on one switch to a config where we've split the nic ports out across the switches. So we now have two vifs split across the switches. Both vifs are on the same subnet and they have separate ip addresses as our switches don't support cross-switch etherchannelling. We currently have everything going through vif1 and this is working just fine. The issue is starting when I start trying to access the second vif, vif2. I can ping vif2 fine, ssh into vif2 fine but when I try to nfs mount an export on vif2 it hangs, waiting, waiting... then mounts it after about 30 seconds (on linux, solaris hosts don't seem to every mount it). But this only happens from some hosts. Other hosts can mount their exports on vif2 just fine.

I took a tcpdump of the process and what appears is happening is vif1 is responding to requests to vif2, for a while, and then eventually responds out of vif2 and the linux servers is then able to mount the export.

I've tried disabling fastpath and this didn't help.

I then started thinking that I possibly need to have the vifs on seperate subnets but netapp support has verified that it should work fine on the same subnet. I'm not getting anywhere fast with netapp support so thought I'd see if anyone else has any ideas.

Thanks,

--
Romeo Theriault