Enthusiast
Enthusiast

vSwitch - network failover/failback

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I have all my vSwitches set up with primary and standby adapters. For the virtual machine switch, there are 4 adapters (two etherchannels) -2 nics primary, 2 standby. These are going to back to a pair of Cisco 6513's. IP has load balancing is set on the vswithch.

I test failover by pinging a guest and pulling cables. When it fails over to the standby, at most it'll miss one ping if that but when I fail it back to the primary by plugging those cables back in, it will consistantly miss 5 pings and then be back to normal.

Does anyone know of a setting that will enable the vSwitch to fail back faster?

Thanks

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Leadership
Leadership

How did you check this?

Cause i also tested this setup, and it did fail miserably. Use ESXTOP from the command line, check with N which nics gets traffic when a cable is pulled.

Duncan

My virtualisation blog:

View solution in original post

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14 Replies
Virtuoso
Virtuoso

What happens if you just use one etherchannel? What load balancing are you using on your vswitch/port group?

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Leadership
Leadership

euuhm this setup is a no go.

what will happen is when the first channel fails a link the first nic of the second channel will join in. in other words their will be two different channels active at the same time. create a 4 link channel instead or drop the channels and use load balancing on virtual port id.

Duncan

My virtualisation blog:

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Enthusiast
Enthusiast

I'm using two port channels as the primary and secondary nics go to different physical switches. If I fail one of the nics in that e-channel, at the most one ping will be dropped. Same failing to the standby nics, it is just failing back to the primary where there is the 5 ping delay.

The load balance policy is IP Hash.

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Enthusiast
Enthusiast

Hmmm. That is not what I see happening: both nics in the first port channel have to fail before the the standby kicks in. If it did what you are saying, my testing would fail miserably.

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Leadership
Leadership

How did you check this?

Cause i also tested this setup, and it did fail miserably. Use ESXTOP from the command line, check with N which nics gets traffic when a cable is pulled.

Duncan

My virtualisation blog:

View solution in original post

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Virtuoso
Virtuoso

It's an interesting Cisco article you posted on your blog Duncan (I read it briefly yesterday) - especially in regards to configuring an etherchannel and using Port ID on the vswitch/port group. We've only ever been able to use IP Hash.... will make some interesting testing on Monday :smileygrin:

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Enthusiast
Enthusiast

I was just testing by pinging a guest. I'll check out with esxtop and report back. Thanks.

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Leadership
Leadership

Indeed Java, it amazed me that cisco prefers port id.... especially when you consider they can do cross stack etherchannels.

Duncan

My virtualisation blog:

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Virtuoso
Virtuoso

Did you manage to get your etherchannel's working with Port ID?

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Leadership
Leadership

No, etherchannels don't work with virtual port id. Cisco says: ditch the etherchannels, go for VST + Virtual Port id + Portfast and connect to 2 seperate switches.

and i guess this makes sense, it's easy and flexible.

Duncan

My virtualisation blog:

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Virtuoso
Virtuoso

Thanks Duncan - I'll pass this onto the netadmin of the site. If Cisco say's to do it - it's gotta be for a good reason. I'd say there will be a number of people out there now questioning their config after reading Cisco's pdf. But then I guess the other side of the arguement will be..... if it works, why change it?

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Expert
Expert

Indeed Java, it amazed me that cisco prefers port id.... especially when you consider they can do cross stack etherchannels.

Duncan

My virtualisation blog:

http://www.yellow-bricks.com

This is an interesting post, thanks Duncan. I just skimmed through it...had a question. On page 23 of the slides it shows a graph of ESX hosts, physical NICs and what looks to be virtual switches (pictured in the middle). Is it showing different hosts connecting to the same vSwitch or am I seeing it wrong? Is this a function of ESX 3.5 that I don't know about? vSwitches are limited to hosts I thought. I could be reading it wrong...

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Leadership
Leadership

it's 1 esx host, the picture is indeed confusing. so the vnic stands for virtual nic, in other words the nic in the VM. weird sheet indeed.

Duncan

My virtualisation blog:

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Enthusiast
Enthusiast

Duncan, right you are, thanks for pointing me to using esxtop to test. I still can't get it to drop any pings with 10 vm's behind the vswitch but I sure am seeing it start using one of the failover nics. I need to be going to redundant switches so I'll remove the etherchannels and go to port ID load balancing.

Randy

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