Comments on: Fixing Erratic Behavior on Hyper-V with Network Load Balancers https://www.altaro.com/hyper-v/erratic-behavior-hyper-v-network-load-balancers/ Hyper-V guides, how-tos, tips, and expert advice for system admins and IT professionals Wed, 31 Mar 2021 06:25:14 +0000 hourly 1 By: Eric Siron https://www.altaro.com/hyper-v/erratic-behavior-hyper-v-network-load-balancers/#comment-3882 Fri, 12 Mar 2021 18:11:00 +0000 https://www.altaro.com/hyper-v/?p=15470#comment-3882 In reply to Aaron.

Is your only symptom dropped packets? I’m not sure that’s so weird. Anything else going on?
Does your tool show that the source of the dropped packets is the load balancer?

]]> By: Aaron https://www.altaro.com/hyper-v/erratic-behavior-hyper-v-network-load-balancers/#comment-3862 Mon, 15 Feb 2021 13:19:00 +0000 https://www.altaro.com/hyper-v/?p=15470#comment-3862 Hello, we are experiencing a wierd issue that I hoped was the one described, but after chaning teaming to “Hyper-V Port” it remains the same.

We see packets being dropped on all nodes, all VMs, almost always at the same time. Even in Hyper-V nodes belonging to different clusters. We do have a physical load balance (FortiADC) balancing VMs in Hyper-V.

We are clueless on what is happening! Any ideas?

]]> By: Shannon Yates https://www.altaro.com/hyper-v/erratic-behavior-hyper-v-network-load-balancers/#comment-3304 Sat, 13 Jul 2019 03:55:00 +0000 https://www.altaro.com/hyper-v/?p=15470#comment-3304 In reply to mikewang.

Hey There,

I have been working witch Cisco, HPE and Microsoft to get to the bottom of this and your the first one i have come across that has found it. We have hit this pretty little issue also in a major way doing migrations of Hyper-V Chassis into Cisco ACI. ACI has a similar feature enabled on the Bridge Domain Called Endpoint Dataplane learning, where effectively it is being clever and learning the MAC IP from the data plane and as a result sees both the Virtual and Redundant physical MAC. This causes MAJOR problems with ACI equivalent to a host flap in the old days followed with Critical Alarms in the fabric.

So If your deploying Cisco ACI any time soon i hope you find this before you migrate in.

Great Post !
Shannon Yates

]]> By: Robert Jones https://www.altaro.com/hyper-v/erratic-behavior-hyper-v-network-load-balancers/#comment-3273 Fri, 31 May 2019 23:29:00 +0000 https://www.altaro.com/hyper-v/?p=15470#comment-3273 This post is super helpful. I have been trying to get to the bottom of this for days. I was about to switch my nic teaming to Hyper-V port before seeing this, but the article solidified it and your explanation is perfect. Thanks so much.

]]> By: mikis https://www.altaro.com/hyper-v/erratic-behavior-hyper-v-network-load-balancers/#comment-3173 Wed, 20 Feb 2019 15:20:00 +0000 https://www.altaro.com/hyper-v/?p=15470#comment-3173 We have been struggling with this magic in the environment with F5 BigIPs and Windows Hyper-V 2012. It was observed only on a certain type of traffic. Mainly DNS/UDP outgoing of the VMs.
We have chosen to disable Auto Last Hop on the F5 as the least painful and the quickest solution for now. Looks it helped.

]]> By: Rob McShinsky https://www.altaro.com/hyper-v/erratic-behavior-hyper-v-network-load-balancers/#comment-2740 Fri, 02 Feb 2018 11:15:00 +0000 https://www.altaro.com/hyper-v/?p=15470#comment-2740 Have seen this ever since Windows Server 2012 Hyper-V, but never before in previous versions. So we had a clue it was due to the new teaming. Struggled with it for our webserver farms. Luckily I had a coworker that was very knowledgeable about the netscaler side and could tell me what was happening on that side. Researching and Switching to Hyper-V mode corrected the problem and has been the standard for our logical switch configurations ever since. Good article. Say hi to Andy if you cross paths.

]]> By: mikewang https://www.altaro.com/hyper-v/erratic-behavior-hyper-v-network-load-balancers/#comment-2739 Fri, 02 Feb 2018 11:12:00 +0000 https://www.altaro.com/hyper-v/?p=15470#comment-2739 Very Cool post

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