Tuesday 26 September 2017

Hyper-V host freezes until LiveMigration finishes

I recently had to rebuild a pair of Windows 2012 Hyper-V hosts that had been 'fiddled' with. The hosts where fully patched and the latest drivers and firmware had been applied.
During a LiveMigration from either host to the other the RDP session would freeze up, typing would be almost impossible. Once the LiveMigration completed the host would return to normality, virtual machines where unaffected.

The network was made up from a pair of Broadcom 57810's teamed together using LBFO, this was configured to be Switch Indipendant and have Hyper-V Port as the algorithm.

Although the hosts where lagged and froze up you could see that in the TaskMgr the LiveMigration network was only using between 2-3 Gbps! However the CPUs show low utilization 6-10%

I checked the Power Profile in the BIOS and made sure it was set to 'Performance' but this made no difference.

We configured the 2x BCM57810 with Jumbo frames 9014 and configured the LiveMigration vEthernet adapter to 9014 bytes and the migrations then hit 9-10Gbps! Further more the laggy-ness and freezing had gone!


Set-NetAdapterAdvancedProperty -Name “NIC1”,"NIC2" -RegistryKeyword “*JumboPacket” -Registryvalue 9014