2008 R2 Hyper-V network issues with VM?

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Nate7311

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I've got a client with a new Dell R720 running 2008 R2 Standard with the Hyper-V Rolle installed running 3 VMs, an old 2003 R2 VM, an 2008 Flat 32bit VM and a 2008 R2 VM.

The 2003 R2 and the 2008 Flat VM were migrated from another box with the implementation of the new server. the 2008 R2 VM is a fresh install as a file server and was fine for approximately 3.5 months. Within the last month, the VM has dropped off the network (no traffic of any kind, in or out) randomly. The VM is still running and active, as I can connect to the console for live administration while the outage is occuring. A quick reboot of the VM solves the communication issue. Since this has happened multiple times, it's not a fluke.

To combat this, I have researched and found a few referenced hotfixes and installed them. All network offload functions have been disabled on all physical NICs, and I have tried another virtual network assigned to another physical NIC.

Got off the horn with MS Tech support earlier without a good feeling as the tech tried to turn on Jumbo Packets on a network not configured for them, but I did get an unpublished hotfix to install, so we'll see...

Any other ideas?
 
I would look for an ipaddress conflict on the network. I've seen similar behavior when that happens. You can test it by changing to a known clear static ip.
 
If the ip address conflict doesn't turn up anything, try removing the network adapter and adding a legacy network adapter and see if your problems go away....downside is legacy adapter is 100mbit only
 
Dump your arp table. I have a similar issue and everytime I dump the arp table I get garbage in their. Only thing I can come up with is a bad network card/switch/cable.
 
Eickst, yeah 100Mbit and lucky to get that kinda throughput out of it. :)

Wrench, I looked at the ARP table, No obvoius FUD in it.

I've got a call open with MS about it, and so far they've had me install an obscure hotfix on both Host and VM that related to IPSEC issues on a VM. I'm assuming that this included an update to the virtual drivers. Back in wait-and-see mode. Thanks for the ideas!
 
I believe there is a hotfix for this exact issue. Something about the network adapter failing under high load. I did randomly experience this on some of our production VMs, where the adapter would just stop working. Logging on the machine directly from the VM host worked, but any attempt to change adapter settings would fail/time out.
 
I don't remember if the hotfix worked on not, as the issue was very intermittent. We have since migrated all of our hosts to Server 2012, and haven't had any of these problems since. Even VMs still running 2k8 as their OS.

Have you changed the advanced adapter settings like disabling Offloading etc?
 
Yup, all offloading has been been disabled. Previously, I'd run into a similar issue running SBS2011 in VM, the hotfix you mentioned resolved that one, otherwise Hyper-V 08R2 has been pretty stable for me.
 
Nate7311 said:
Yup, all offloading has been been disabled. Previously, I'd run into a similar issue running SBS2011 in VM, the hotfix you mentioned resolved that one, otherwise Hyper-V 08R2 has been pretty stable for me.
Click to expand...

Tha'ts a really interesting problem. I had bad experience with the 8 and 8r2 hv. Used vmware but I ran into problems with networks dropping with vmware and srv 2012 I've found a fix so far. I do like hv2012 much more the 8r2.
 
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